A deadbeat decoupling control method of Z-source photovoltaic grid-connected inverter is proposed. This method overcomes the disadvantages of conventional PI control method such as sensitivity to the unbalance of the grid system and no-linear characteristic. The proposed control algorithm combines deadbeat and decoupling method. In order to minimize the error caused by the program executing and sampling time， the dual-timer sampling method is used. This control strategy is good at response speed， high accuracy and stability. A modified space vector pulse width modulation algorithm is used to realize the boost ability of Z-source. The current injected into grid is synchronous with the grid voltage， so a unity power factor is realized. Simulation and experiment results both validate the feasibility of the proposed algorithm.