Intelligent valve positioner is the control unit for eletrictro-pneumatic valve. For intelligent valve positioner，valve position control algorithm plays one important role in valve lever postion and valve opening control. The conventional five contact switching control algorithm is characteristic of simplicity and rapid responding, but also blamed for difficulties of parameters adjusting and bad control robustness for different valve cores and travel distance. This paper developed a valve position control algorithm with the five contact switching and PID control strategies integrated. In this algorithm, the PID initial parameters were determined in the system initialization program and then were adaptively trimmed in the process of valve positioning control. The result of valve positioning control experiments showed that this adaptive control algorithm realized precise control of valve positions and met the requirement of positioning error below ± 1% F. S.