Complex [Cu(Gly-Gly)(Im)]·2H₂O(s) was prepared by mixing the solution of copper sulfate pentahydrate, glycylglycine and imidazole. The crystal structure of [Cu(Gly-Gly)(Im)]·2H₂O was determined by X-Ray single crystal diffraction. The crystal belongs monoclinic with space group P2₁/n and unit-cell parameters are a=1.0213(6)nm, b=0.7023(4)nm, c=1.5911(9)nm, β=102.393(9)°, V=1.1147(11)nm³, and Z=4, respectively. The dissolution enthalpies of CuSO₄·5H₂O(s)+Gly-Gly(s)+Na₂SO₄(s), Im(s) and [Cu(Gly-Gly) (Im)]·2H₂O(s), 2NaHSO₄·H₂O(s) have been determined in 2mol/L HCl solution by the classical solution calorimetry. According to Hess law, a thermochemical cycle is designed. By calculation, the reaction enthalpy of CuSO₄·5H₂O(s)+Gly-Gly(s)+Im(s)+Na₂SO₄(s)=[Cu(Gly-Gly)(Im)]·2H₂O(s)+2Na·HSO₄·H₂O(s)+H₂O(l) is calculated, Δ_rH_m^θ(298.15K)=(36.763,4±1.132,5)kJ/mol, and furthermore the standard formation enthalpy of [Cu(Gly-Gly)(Im)]·2H₂O(s) has also been calculated, Δ_rH_m^θ{[Cu(Gly-Gly)(Im)]·2H₂O(s), 298.15K}=(-1,770.3±1.4)kJ/mol.