Path planning for dual aircrafts is preceded by artificial immune algorithm in forest fire rescue. We analysis and compare several parameters which will influence path planning. Based on above results we sum the reasonable parameters which should be used in further experiment. Moreover, to improve the operability of aircraft, restrictions of gradient smoothing algorithm, curvature smoothing algorithm are performed to smooth track in vertical aspect. Experimental results show that we can successfully get the satisfied flight paths for dual aircrafts in fire rescue under complex circumvent. At the same time the paths we planned have certain practical value by consideration the aircrafts fly-ability constraints.