Abstract: Affected by reservoir and thermal fluid physical properties, well pattern of development,injector-production relationship and other factors, the gas channeling between wells is serious in Bohai oilfield during heat injection period, the thermal production effect of single well in the stimulation cycle becomes worse, the adjacent well production decreases, and then the normal production cannot be achieved.Therefore, the blocking technology of temperature sensitive gel was applied to restrain gas channeling, the mechanism of temperature sensitive gel assisted polythermal fluid was analyzed, the relevant characteristic parameters were determined by experiments, and the main parameters affecting the blocking property of temperature sensitive gel were optimized by numerical simulation. The field test results show that the adjacent wells can be produced normally without obvious gas channeling phenomenon during the thermal production, and the good application effect has been obtained on the whole, which provides a technical support for the prevention and control of inter channeling flow in the subsequent thermal production wells at sea.