In order to detect the slow and small target (SST) of can be detected that the radar operators often mistake it as a clutter point because of large clutter interference intensity, weak target echo and other reasons. The continuous multiframe radar image has been accumulating for a long time, aiming at the problem that the target echo is not connected in the multiframe radar image accumulation, a detection method for SST based on target echo disconnection is proposed. The parameters of the minimum circumscribed rectangle, consisting of Fj3、Fj2 and Fj1,and these parameters are extracted in the target accumulation echo by image marking technique, the interference of the large target connected echo to the SST is eliminated by Fj1,the H(Aj) obtained by Fj2 and Fj3 classifies the target accumulation echo, according to the moving distance α of SST multiframe accumulation time. In each classification filed, the target with the target echo distance greater thanαthe target is filtered, then through the “SST determination” to achieve SST effective detection. Finally, the SST detection results in classification domain are synthesized to obtain the final SST detection effect. Simulation results verify the effectiveness of the proposed algorithm.