The effects of three organic copper salts,such as copper 2,4-dihydroxybenzoate(β-Cu),copper 3-nitro-1,2,4-triazol-5-onate(NTO-Cu) and 2,4-dinitroimidazole copper(NI-Cu) salt on combustion characteristics and thermal decomposition of RDX-CMDB propellants were studied at different pressures. Results show that the effects of organic copper salts on the combustion and thermal decomposition characteristics values of RDX-CMDB propellants are obvious. The three organic copper salts can accelerate the thermal decomposition of RDX-CMDB propellants. β-Cu,NTO-Cu and NI-Cu can move up the first peak temperature about 1-4 ℃,and move up the second peak temperature about 5-11 ℃ of RDX-CMDB propellant. The burning rate and thermal decomposition characteristics values of the RDX-CMDB propellants increase with increasing of pressure. The burning rates of RDX-CMDB propellants are related to the thermal decomposition characteristics values of RDX-CMDB propellants at 1-10 MPa.