Energy supply is crucial to robots' application. Air-breathing proton exchange membrane (PEM) fuel cell is adopted to supply power for motors. Based on the analysis of energy conversation and thermal exchange of PEM, a thermal model was developed for analyzing the temperature control method. The stack inside temperature is crucial to output power of fuel cells. A practical stack temperature optimization method was designed. Through experiments on the independent developed test-bed, the optimal temperature under different output current and voltage were analyzed and given in curves. The three-order polynomial approximation function was established to describe the relations between optimal temperature and current or voltage. Considering varying parameters, delay and noise, the fuzzy incremental PID control of temperature was designed and fuzzy rules were given. Weighted averaging algorithm was used to anti-fuzzy. Control test-bed was developed using MCU and K-thermocouple. Control tests were done and results indicate that optimal temperature is valuable, and the controller and control scheme are valid. An autonomy power supply idea was discussed in end of this paper.