Abstract: Temperature coefficients for themodynamic function are determined by means of a simultaneous least-squares fitting of heat-capacity,enthalpy、entropy,which are described as polynomical equations in temperature.After some mathematical treatments and programming,exact numerical solutions can be obtained.Even some of solution errors are less than those given in reference[1]、[2].The first and systematical calculation of the temperature coefficients for combustion products of the copper element has been completed.The function ensures the equal values at the cross point of the two temperature intervals(such as 100K).In fact,this method provides the reliable data of the temperature coefficients for the calculation of the propellant performance.