| In the non-isolated photovoltaic inverter system, the common mode interference problem of the photovoltaic array is serious. It is often neces-sary to add an electromagnetic interference filter to the DC side and the AC side of the inverter, but there is a lack of analysis for the design trade-off between the AC side EMI filter and the DC side filter and the coupling between the two. After analyzing the filter coupling characteris-tics, a floating structure EMI filter is used on the AC side. The experimental results show that this structure can eliminate the coupling effect of the EMI filter on the AC and DC side, so that the EMI filters on both sides can be designed independently. At the same time, it can enhance the common mode attenuation capability of the EMI filter on the DC side and the AC side, and effectively suppress the common mode interference of the photovoltaic.