The invention relates to a magnetic integration device for realizing magnetic integration of a three-phase transformer and a three-phase LCL filter in a three-phase circuit, the three-phase LCL filtercomprising three first inductors close to the three-phase transformer and three second inductors away from the three-phase transformer. The magnetic integration device is characterized by comprisingmagnetic core bases parallel to each other, and a common magnetic column and at least two coupled magnetic columns between the magnetic core bases; any coupled magnetic column is used for winding anypair of primary and secondary coils of the three-phase transformer or winding coils of at least two first inductors; the coupled magnetic columns are provided with air gaps, while the common magneticcolumn is not provided with any air gap. By integrating part of or all of coils of the three-phase transformer and the three-phase LCL filter from the magnetic structure and setting the common magnetic column, the integrated total flux flows to the common magnetic column. Therefore, three-phase imbalance caused by imbalance of single phases is avoided while the size and weight of the three-phase circuit are reduced.