This dissertation analyzes the advantages and disadvantages of those methods and air bearing method is chosen to build the gravity unloading facility. Based on the structure characteristics of antenna pointing mechanism and performance test requirements, research on the air bearing facility for the antenna pointing mechanism is completed. Mainly including the following aspects: First of all, a hierarchical and simultaneous gravity unloading method is proposed based on the characteristics of antenna pointing mechanism and performance test requirements. This method can unload the gravity of both joints of antenna pointing mechanism respectively. The artificial load is designed for replacing the satellite antenna to test the performance of antenna pointing mechanism. The antenna pointing mechanism consists of two orthogonal joints. The gravity of both joints should be unloaded respectively to simulate microgravity environment. Planar air bearing and air spindle are applied to unload the gravity of antenna pointing mechanism and artificial load in the proposed gravity unloading method. The artificial load is designed under the constrains of mass, momemt of inertia and frequency to truly reflect the physical characteristics of satellite antenna. A design method based on given frequency is summarized based on the artificial load design. The correctness and effectiveness of the gravity unloading method are preliminarily verified by structure design and simulation in ADAMS software. Secondly, the kinematics and dynamics models of gravity unloading facility and running state in space are derived respectively, then similarity analysis is completed. Thus the hierarchical and simultaneous gravity unloading method proposed is verified theoretically. D-H parameter method and the Newton-Euler method are applied to derive the kinematics and dynamics models based on the analysis of gravity unloading method and the structure of facility. Multiple unloading forces are introduced to eliminate the influence of gravity on the joints when trying to get the microgravity environment. Therefore, the force balance equations of the related links are modified when deriving the kinematic model with Newton-Euler method. By comparing the force and torque of two joints of the antenna pointing mechanism in two models, the effectiveness of the unloading method is further verified. Then the similarity criteria between air bearing facility and running state in space are derived by using the similarity principle based on the kinematics and dynamics models. The approximate similarity analysis method is used to derive the degree of similarity between the two models. The result shows the reliability of the air bearing facility from another aspect. Thirdly, the gravity unloading precision of this facility and the items which affect the precision are quantitatively analyzed. So the performance of the facility itself is evaluated. The main purposes of this facility are unloading the gravity and testing the performance of antenna pointing mechanism. The angle precision and torque of two joints are the main parameters to test among which the torque of two joints reflects the gravity unloading precision. So the items which affect the torque are found and analyzed, including the forces of adjustable spring mechanisms, the balance level of horizontal joint load, the coaxiality of horizontal joint and air spindle, the viscous resistance of planar air bearing and air spindle, and the level degree of granite platform. The weight coefficients of all items are derived by analytic hierarchy process, then the gravity unloading precision is obtained. Finally, the air bearing facility is built based on the proposed method and structure design, then experimental research on this facility is completed. The level degree of granite platform is measured, the effectiveness of air bearing components is tested by turning on and off the pneumatic circuit, coaxiality between air spindle and connectors at both ends of air spindle is measured, the unbalanced torque of horizontal load is also measured. At last, the gravity unloading precision is measured by comparing the output curves of torque sensors on both joints with the theoretical curves. The correctness of the unloading method, simulation and theoretical analysis are further proved by these experiments. The main contributions and innovations of this dissertation are as follows: (1) A hierarchical and simultaneous gravity unloading method is proposed. This method can unload the gravity of two joints of the satellite antenna pointing mechanism and provide the microgravity environment on the ground. (2) A structure is designed to decouple the rotational inertia moment of two orthogonal joints; a structural optimization design method based on given frequency is proposed, and the structure design can be completed under constraints of given mass, moment of inertia, and frequency; (3) Force balance equations in dynamic model derivation with Newton-Euler method are revised by adding the corresponding items of unloading force, which show the purpose of unloading forces.