The cooperative search with double-plane IRST system is an important passive detection method.Analysis is made to the key problems in double-plane IRST system cooperative search,and the mathematic model for autonomous guiding search is established.Through the target angle information detected by IRST system of the lead aircraft,the angle range of target in the wing aircrafts body axis system is obtained by using detection distance coverage limits of the IRST system.Then,the IRST system of the wing aircraft is guided to search the target area according to the angle range.Two search methods,sequential searching and central searching,are put forward for IRST system of the wing aircraft.The simulation result shows that the autonomous guiding search is effective,and the central searching is more efficient and takes less time.The successful guiding probability is verified by the simulation results of two schemes according to the central searching strategy.The conclusions are helpful for designing double-plane IRST guiding systems.