With the rapid development of optoelectronic imaging technology,stray light interference phenomenon has become a difficult problem for optoelectronic systems to avoid.In order to better characterize the stray light degree of visible optical system and to solve the problem that the existing evaluation method,PST algorithm,cannot characterize the total energy and energy distribution of stray light incident on the image plane,an optimized equivalent PSTη calculation method is proposed in this paper.Taking a visible optical system as an example,the stray light data of each off axis angle of sunlight relative to the optical axis of the system are obtained by stray light simulation software,and the original PST algorithm and the PSTη algorithm are compared with the stray light irradiance analysis diagram,respectively.The results show that the PSTη algorithm can more accurately represent the stray light change trend when the traditional PST calculation values are consistent,and thus can better characterize the stray light distribution of visible light systems.The PSTη is used as an evaluation index to design stray light suppression measures for visible optical systems,and the ability of PSTη to guide the actual stray light analysis and suppression work is verified.The evaluation index can also be extended to other wavelength imaging systems.