Both thermal decomposition behaviors and non-isothermal decomposition reaction kinetics of propyl-nitroguanidine (PrNQ) were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) method. Its decomposition mechanism was stuied through in-situ FTIR spectroscopy technology and the compatibilities of PrNQ with 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (HMX), hexanitrohexaazaisowurtzitane (CL-20) and 5,5′-bistetrazole-1,1′-diolate (TKX-50) were also achieved by DSC experiment. The results show that the melting point of PrNQ is around 99 ℃, which is very suitable for the application of melt-cast technology. The thermal stability of PrNQ is good and the difference between the melting point and decomposition temperature of PrNQ is about 137 ℃, which is large enough to guarantee the safety of the melt-cast process. The compatibilities between PrNQ and HMX or TKX-50 are also excellent, with ΔT_p of -0.3 K and 1.36 K， respectively.