temperature effects on the open circuit voltage, short circuit current, fill factor and conversion efficiency were studied using conversion characteristics of photovoltaic cells (PV cells). Moreover, the temperature characteristics of output efficiency for polysilicon PV cells were studied by experiment. Theory research results show that the decreasing rate of open circuit voltage and fill factor(FF) are -2.3mV/K and -4.5×10-4/K, the increasing rate of short circuit current is 1.21mA/K. Thus, the conversion efficiency of PV cells would decrease with temperature increasing of PV cells. In addition, the decreasing rate of the output efficiency of polysilicon PV cells is -0.22%/K based on experiment results. The experimental results are consistent with the theoretical analysis. The results provide a theoretical and experimental basis for the optimal design of photovoltaic systems.