Abstract: Energy system of the equipment used to make diamond film by the direct current-plasma jet (DC-PJ) was studied. Based on analyzing mechanism of heat transfer, the theory and experiment which research the level of varies of factors and the relationship of the factors were introduced. Five mathematic models according to temprature distrbution, radiation,convection,transference and heat balance were set up and calculated by this program, and got a consistent result both by calculation and by experiment.