In order to solve the problem that the traditional modeling detection algorithm for spotted small target is susceptible to the dim and spotted targets, resulting in the loss of small target or the false detection that treat the background information as the target during the detection process, a more effective multi-scale spotted small target modeling algorithm was adopted. By modeling the background and suspicious target, the suspicious target image could be obtained. Finally, a threshold segmentation algorithm was used to extract the real target from the suspicious target, and then the theoretical analysis and experimental verification were carried out. The results show that under the same data set, the trajectory of small target dected by this algorithm is closer to the real trajectory than those by other algorithms. This research is helpful to improve the accuracy of small targets detection.