Abstract: Tian's equation is taken as a theoretical model of conduction calprimerer, and the changing states of a reacting system is described with the extent of reaction. And then thermokinetic equations of the whole system (thermokinetic system) have been derived in the light of nonequilibrium thermodynamics.The rate law of a thermokinetic system and analytical expressions of thermokinetic curves can be derived from the thermokinetic equations respectively. On this theore-tical basis, a new studying method of thermokinetics has been suggested in this paper.