LCL filters are widely used in grid-connected devices because of their superior high-frequency harmonic attenuation and filtering effects, but their parameter design is more complicated. An new LCL filter parameter optimization design scheme was proposed based on genetic algorithm in this paper and a multi-objective optimization design model which have minimizes ripple current, maximizes harmonic attenuation, and minimizes power loss was established.Using entropy weighting method to convert to single objective optimization model and using genetic algorithm to solve optimization model in this paper. Meanwhile, the Grid-connected inverter based on LCL filter simulation model was built in Matlab/Simulink and the simulation results verified the applicability of the design. Compared with the existing methods, the optimization scheme has better harmonic attenuation performance, the ability to suppress ripple and less power loss while ensuring the filtering performance.