The echoes of surface movement radar (SMR) are real aperture images with high resolution, which is difficult for traditional radar target de tection method to dea l with. Firstly, the problem in SMR target detection is analyzed. Then a new SMR target detection algorithm according to the characteristics of SMR echo is proposed , based on the digital image processing. The flow chart of th e algorithm and the realization of the main components are described in detail s eparately. The processing result of SMR return signal collected from certain air port is presented to reveal the validity of the proposed algorithm. The target c an be detected effectively. A mass of isolated false alarm points are removed an d th e cavities inside the target region are filled by target cluster aggregating pro cessing.