A mixed ligand complex of manganese(Ⅱ) carbohydrazide azide, Mn(CHZ)₂(N₃)₂ (CHZ=carbohydrazide), was synthesized and characterized by using elemental analysis and Fourier transform infrared (FTIR) spectrum. Its crystal structure was determined by single crystal Xray diffraction analysis. The crystal belongs to triclinic, Pī space group, a=8.2217(17), b=8.7427(18), c=9.4532(19), α=86.376(4)°, β=69.104(3)°, γ=74.019(3)°, V=609.8(2)A³, Dc=1.738 g·cm^-3, Z=2, R₁=0.0316, wR₂［I>2σ(I)］=0.0826 and S=1.132. The central Mn(Ⅱ) ion is sixcoordinated with two carbohydrazide molecules and two monodentate azido ligands, and carbohydrazide serves as bidentate ligands through the carbonyl oxygen atom and one of the terminal nitrogen atoms. The thermal decomposition mechanism of the complex was studied by using differential scanning calorimetry (DSC), thermogravimetryderivative thermogravimetry (TGDTG) and FTIR techniques. Results show that the final residue of thermal decomposition at 500 ℃ is MnO.