Abstract: In order to meet the development needs of precision-guided munitions intelligence and generalization,the seeker needs to adopt dual-mode or multi-mode compound system.Compound seeker design has been a complex system work,needing not only to meet the overall tactical and technical requirements of missiles,but also to balance the mode coupling and competitive relations.Among the design works,the compound detection system design is the key work.In this paper,the key technologies included in the design of general and compound detection system were discussed for semi-active laser/infrared imaging/active millimeter wave three mode seeker,focusing on the advantage and disadvantage analysis of several compound detection system schemes.The general design of a compound detection system was carried out based on an inverse method of the range index to caliber size.Simulation results show that the performance of three modes can meet the system requirements,and the compound detection scheme is reasonable and feasible.