Abstract: BP algorithm is the major imaging method of GPR and is performed by adjusting the echo time-delay. Because the dielectric property is different between the medium subsurface and air, the electromagnetic wave would change its propagation path and velocity. The real-time propagation path is needed to be calculated during the calculating of time-delay. The computational load is heavy and the efficiency is low. In order to overcome this shortcoming, migration method is adopted in this paper. By the processing of the experimental data, migration method is applied in the imaging of subsurface target successfully. The computational load is decreased and imaging efficiency improves at the same time.