The multi-group circular fringes on the optoelectric detector were observed in the experiment of laser disturbing optoelectric imaging systems. The method of disassembly, measurement, modeling and ray tracing of optical system was used to investigate the formation mechanism of multi-group circular fringes. First of all, the radius of curvature, thickness, pupil of every lens were measured and the model of optical system in TRACEPRO software was built. Based on the model, large number of random rays to propagate in the optical system were traced secondly and the energy distribution on the optoelectric detector was obtained. By analyzing the origin of every energy component, it was found out that the multi-group circular fringes were caused by interference effect of the different energy component on the optoelectric detector. The research results can provide the technical support for evaluating laser disturbing effect on optoelectric imaging systems.