According to the characteristics of the zero-sequence current in the distribution system, a stereoscopic zero sequence filter structure is proposed. The icon cores are symmetrically arranged in a triangular space. Compared to the conventional planar reactor, the triangular structure has a symmetrical magnetic circuit which can solve the problem of the three-phase imbalance and enable three-phase zero sequence flux to be consistent. In the zero-sequence filter, the value of the zero sequence impedance is an important parameter which has a direct impact on the filtering effect. In order to obtain an accurate zero sequence impedance for the structural design, the distribution of the zero-sequence flux is theoretically analyzed, and a simplified symmetric model in ANSYS is given. Then the zero-sequence impedance is calculated using the energy method based on the ANSYS software. Finally an experiment is carried out. The result of the experiment verifies the correctness of the calculation. It provides an effective engineering method for the zero sequence impedance design of the stereoscopic zero-sequence filter.