As power electronics move to high switching frequency, electromagnetic interference (EMI) is receiving increasing attention. The application of digital active EMI filters (DAEF) effectively reduces the size of passive filters and improves the applicability of AEF. However, the characteristics of noise sources change with the changing working conditions, which requires greater adaptability. Therefore, this paper designs an adaptive DAEF based on the LMS algorithm. A delay compensation algorithm is also proposed to address the delay issue introduced by the system's secondary path.