Abstract: Through the analysis of the traditional dual-band target simulator, a target simulator using only one generator and one projection system was put up to solve the problem of high cost and relatively complex structure. Using the method of division of amplitude, by the filtration of the filter and shading sheet, the energy of the two bands could transmit according to a specific proportion ,and in the specific integral time, detector could detect different energy ratios of the two bands, which could be used to simulate different infrared targets.Futhermore, the optic design of the projection system in the scheme was conducted.The projection system uses transimission model,which works in 3.3 m~3.8 m/4.4 m~4.8 m with a half field of view of 2.2 and an F number of 3.2 ,the system resolution could reach 10 lp/mm. The improved simulator can simulate the infrared objects of black body ,gray body,even selective body （300 K~3 000 K），with the radiation energy larger than the detected minimum energy ,proving scheme feasible .