The self⁃made thermocouple, self⁃made double parallel conductivity probe, Labview programming system and IMP temperature programming system were used to obtain the phase distribution characteristics of oil⁃water two⁃phase flow, and the interaction between flow pattern and flow parameters and heat transfer coefficient was analyzed. The results show that the cooling flow process affects the flow pattern distribution, which means the range of oil⁃in⁃water and mixed interface layered flow and water⁃in⁃oil flows with cooling convection heat is smaller, but the stratified flow, water⁃in⁃oil & oil⁃in⁃water and oil⁃in⁃water & water flow types have a larger range on the flow chart, and flow pattern transition boundary between the two is higher, and the trend of higher oil velocity and water velocity is developed. The heat transfer coefficient is closely related to the flow pattern and flow velocity. The low flow velocity is mainly affected by the flow velocity, while the high flow velocity is mainly affected by the flow pattern.