The invention discloses a method for controlling a Z-source three-level four-bridge-arm photovoltaic inverter, which includes the following steps: first, modulation waves m*a, m*b and m*c are respectively compared with carries C1 and C2 to get logic signals S1a, S2a, S1b, S2b, S1c and S2c; then, addition operation is carried out on S1a, S2a, S1b, S2b, S1c and S2c through a logic circuit to get vectors SA, SB and SC, a modulation strategy is implemented on the vectors SA, SB and SC through a fourth bridge arm to get vectors SA, SB, SC and SD, and correspondence is carried out on the vectors SA,SB, SC and SD in the logic circuit according to a corresponding correspondence to get 16 logic signals g11-g44; and the carriers C1 and C2 are compared with VH and VL to get a direct signal D, and switching signals S11-S44 are obtained through the logic circuit according to the 16 logic signals g11-g44 and the direct signal D. Through the control strategy presented in the method, the leakage current problem of the Z-source three-level four-bridge-arm photovoltaic inverter is solved, and the utilization rate of the DC voltage of the system is high. Moreover, the control scheme presented by theinvention is simple in circuit structure and easy to implement.