As the traditional decoupling control method of d - and q -axis components of the grid current is realized by adding the minus q -axis and positive d -axis components of the grid current multiplying inductive reactance of the total filter inductance into the output of the grid current controller， respectively， the grid-connected inverter has poor waveform quality of the grid current. As the three-phase-leg voltage cannot directly reflect the change of the reference grid current with the traditional decoupling control method， the grid-connected inverter has slow dynamic response. In order to solve the problems， the d - and q -axis components of the grid current in the decoupling components of the grid current controller is substituted by that of the reference grid current. The operating principle of the traditional and improved decoupling control methods is illustrated. Experimental results on a 15 kVA three-phase grid-connected inverter with SVPWM verify the theoretical analysis. Compared with the traditional decoupling control method， the grid-connected inverter with the improved decoupling control method has high waveform quality of the grid current， small ripple power and fast dynamic response.