The sliding friction of the friction pair of wet clutch involves the strong coupling process of multiple physical fields such as temperature field, stress field and strain field, which makes the thermal expansion characteristics of the friction pair highly nonlinear. At the same time, the temperature field of the friction pair is affected by many parameters. In order to deeply study the temperature field characteristics of the friction pair in the engagement process of the wet clutch, the analysis model of the friction pair of the wet clutch is established to effectively simulate the interaction of temperature, stress and strain in the sliding process. On this basis, the effects of initial speed, engagement oil pressure, dual steel plate thickness and friction lining material on the temperature field of friction pair are deeply studied, so as to provide a theoretical basis for the design optimization of wet clutch.