Abstract: As the traditional analog signal guidance law can not be used directly when dealing with the question of unmanned aerial vehicle(UAV) load data link,a kind of non-buffet discrete variable structure guidance law based on mode reference is proposed.This arithmetic uses the robust of variable structure control to guarantee the guidance precision.even if the coordinate of targets measured by on early warning aircraft has error,or the targets move with high flexibility,the guidance still has the strong anti-interference capability.And a kind of non-buffet discrete variable structure control algorithm is also proposed,which overcomes the buffeting phenomenon of the traditional discrete variable structure control algorithm that happens after getting in sliding mode.The simulation results show that the proposed discrete signal guidance law can meet the tactical UAV indicators.