The invention provides a correction method for relative installation errors between a seeker and an inertial measurement unit system. The method comprises: determining an installation angle of an initial antenna, performing flight tests to acquire data, performing image screening to obtain position information of a target in an image, determining coordinate values of the target in an ENU coordinate system with a carrier mass center as an original point, determining coordinate values of the target carrier in a posture coordinate system, and determining an antenna installation error correction value and correcting the installation angle of the initial antenna. The method dynamically and accurately measures under a test state, and comprehensively uses carrier posture information, position information, radar system parameters, and seeker imaging images and other data, and installation error correction precision and test data validity are improved.