Tensegrity robots are novel flexible mobile robots based on the conception of “tensegrity structures” that cited from the architecture. Tensegrity robots possess high strength-mass ratio, deformation capacity and shock resistance ability and can adapt to the environment with self-deformations. Existing simulations for tensegrity robots are carried out with Matlab that required complex dynamics modeling process and additional force constraints. Using ODE (Open Dynamic Engine) as a simulation tool can avoid the cumbersome modeling process. However, the robot model would collapse with the growth of DOFs (Degrees of Freedom). This paper solves the stable problem caused by large number of DOFs and builds a simulation environment for 6-strut tensegrity robots. Dynamic simulations for rolling and crawling gaits are performed in the simulation environment.