Abstract: To verify suppression capability of the stray light of the lunar-based optical telescope (LOT), its stray light rejection ratio of glare shield out of field range by point source transmittance on ground was tested, and assessing its stray light rejection ratio with PST of optical system diversity angle of offaxis. The new test method of PST breaks through the tradition method of stray light, using a new method that is combining high degree of accuracy star simulator with EMCCD, guaranteeing that the detector has large dynamic region within its linear range, and the dynamic range is 1012. It could satisfy the indexing demand that the PST testing result is 10-7 (at 22angle of off-axis). This test method could objectively and directly reflect the stray light rejection ratio of glare shield. The testing uncertainty of PST is above 60%, it will exceed the testing precision of classical stray light testing method. Moreover, discussing the improving method,the target PST testing result will reach 10-12. Last it verify the PST of LOT catering design demand with the experiment that it test stray light rejection ratio of glare shield.