It is known that resonance of LCL filter may lead to instability of grid-connected inverters.A dual-loop current control strategy based on capacitor current loop is introduced to deal with the resonance problem of LCL filters.However，the tuning procedure is complex because the outer-loop and inner-loop controllers would not be operated well if the parameters of the controllers are not suitable in traditional methods.An integrated parameters design and optimization method is presented.The controller parameters are acquired by less degrees of freedom（DOF）pole assignment，and the parameters are optimized with integral of time multiplied by the absolute value of error（ITAE）performance index under certain stability margin.The proposed method is superior to traditional trial-and-error methods and shown to be robust.Experimental results verify the conveniences and the good dynamic and steady state performance of the proposed method.