In this paper, the effect of electron temperature on the characteristics of plasma sheath in the channel of Hall thruster is studied by using two-dimensional (2D) particle-in-cell simulation method. The change laws of electron number density, sheath potential, electric field and secondary electron emission coefficient at different electron temperatures are discussed. The results show that when the electron temperature is low, electron number density decreases exponentially in the radial direction and reaches a minimum at the wall, the sheath potential drops and variation of electric field in the radial direction is larger, and the wall potential stays at a stable value, the stability of sheath is better. However, when the electron temperature is high, the electron number density inside the sheath region approximates to that at the sheath boundary, but in a narrow area near the wall it increases rapidly and reaches a maximum at the wall, sheath potential changes slowly, the sheath potential drops and variation of electric field in the radial direction is smaller, and the wall potential tends to maintain a persistent oscillation and the stability of sheath is reduced. The influence of electron temperature on electric field in the axial direction is small. With the increase of the electron temperature, wall secondary electron emission coefficient increases in the early stage, and reduces later.