Five kinds of composite explosives containing 1, 1-diamino-2, 2-dinitroethene(FOX-7) were prepared by mixing FOX-7 with five kinds of commonly used single-compound explosives, cyclotrimethylenetrinitramine(RDX), triaminotrinitrobenzene(TATB), 2, 6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105), cyclotetramethylene tetranitramine(HMX), hexanitrohexaazaisowurtzitane(CL-20) in the mass ratio of 1:1 respectively. Effect of temperature on the crystal phase transformation of FOX-7 in the composite exposives were studied by a variable X-ray powder diffraction technique. In the process of temperature increasing, the α→β crystal phase transformation of FOX-7 in five kinds of composite explosives occurs at 105-125 ℃. The β→γ crystal phase transformation of FOX-7 in FOX-7/HMX and FOX-7/LLM-105 composite explosives does not occur. In the process of temperature decreasing, the γ→α crystal phase transformation of FOX-7 in FOX-7/RDX composite explosive occurs directly. The crystal phase transformation of FOX-7 in other three kinds of composite explosives is reversible in the cooling and heating process, i.e. in the cooling process, the crystal phase transformation occurs from γ or β to α.