Abstract: On the basis of velocity fields of three dimensional parabolic flow in oil grooves of wet multiple disc brakes,the control volume method was used for computing of temperature fields in the oil grooves when the friction plate moves in various velocities. With the boundary layer theory, this paper derived the variation law of average heat transfer coefficients between the friction plates and the oil flowing in the grooves in the radial direction, and provided theoretical basis for designing a new wet multiple disc brake.