Abstract: The high level penetration of photovoltaic（PV）power generation into large-scale AC-DC power grid from the sending and receiving area significantly changes the transient response characteristics of the power grid, and puts forward new requirements for the control and operation of the power grid. In this paper, the influence of high level PV penetration on transient voltage of receiving grid was studied based on rational fraction fitting method. Firstly, the feasibility of introducing rational fraction fitting method into power grid transient analysis was proved, based on trapezoidal integration and Cramer’s rule. Then, a simulation scenario for a receiving system with high level PV penetration was established, the parametric relationship between the PV terminal voltage and the control parameters of the inverter during the fault-on and recovery stage was studied by rational fraction method, which showed the effectiveness of the proposed method.