Photovoltaic system simulator is under being developed for the performance test of Power conditioning system (PCS). The photovoltaic system simulator is required to emulate real system, which can be obtained by fast response controller. In this paper, we suggest a robust control method as a tool to design the simulator controller. The performance of the controller is determined by weighting functions, sensitivity function $W_1$ complementary sensitiviey function $W_3$, and a control signal shaping function $W_u$. Experimental results show that robust control method is promising for obtaining better performance of the photovoltaic system simulator.