A phase state control model of supercritical CO2 (SC-CO2) fracturing by temperature control has been developed on the basis of CO2 physical properties, fluid filtration characteristics, internal energy, and flow work variation in the fractures. A considerable amount of analysis focuses on the effects of the CO2 injection temperature and pressure, geothermal gradient, pumping rate of CO2 fracturing fluid temperature, pressure field, and phase behavior in the wellbore and fractures. In this study, the phase control method of the fractures during SC-CO2 fracturing in addition to its chart is obtained. The results indicate that the temperature of the SC-CO2 fracturing model in the wellbore and fracture is less than that when not considering the flow work model at the same location. During the process of fluid flow, a transition occurs from the liquid to supercritical state in the wellbore or fractures. The phase transformation point differs in the fractures such that a lower injection temperature relates to a high pumping rate, lower geothermal gradient and closer location of transformation point to the end of fractures. Thus, to obtain the optimal stimulation effect of the supercritical CO2 fracturing, the phase behavior of CO2 should be controlled according to the reservoir conditions through surface equipment by optimizing the injection temperature, pressure, and pumping rate of the fracturing fluid. (C) 2017 Elsevier Ltd. All rights reserved.