The invention relates to a micro-grid harmonic suppression method based on an interval optimization algorithm. The method is technically characterized by comprising the steps as follows: step 1, a micro-grid harmonic suppression optimization model based on the interval optimization algorithm and constraint conditions of the model are constructed, and a target function is the harmonic voltage distortion rate of a micro-grid access point; step 2, the value of the micro-grid harmonic suppression optimization model based on the interval optimization algorithm in the step 1 is solved through combination of target function optimization and equality constraint conditions, when the harmonic voltage distortion rate of the micro-grid access point is minimum, the LC filter parameter configuration issolved with a branch and bound method. The method has stable convergence and high calculation accuracy, can stably converge to obtain the globally optimal solution and is applicable to LC filter parameter configuration under micro-grid harmonic suppression.