The capture probability of the seeker when midcourse guidance switches to terminal guidance is the core for the design of the combined guidance air-to-air missiles, and is very important for the overall design of the missile.In this paper, the effect of data link error on intercept probability of infrared air-to-air missile after launching was studied.The results show that the data link errors have a great influence on performance of missile capture.The results can be taken as a reference for the design of lock-on-after-launch missile.