To countermeasure semi-active laser-guided missile,laser angle deception interference is an effective means.In order to improve the combat effectiveness of laser angle deception interference and save interference resources,the probability model of the interference signal admitted by the wavegate of the seeker is established on the basis of theoretical analysis,the optimal lead time for angle deception interference of the semi-active laser-guided missile is studied,and a laser angle deception interference method of progressive interference lead time is proposed.The simulation results show that there is a correspondence between the ratio of the wavegate width to the error of the indicator signal and the probability of successful guidance.When the wavegate width is fixed,there is an optimal interference lead time so that the interference lead probability is the greatest.The interference efficiency of the laser angle deception interference method of progressive interference lead time is high,which has certain practical value.