The finite element model of the hydroviscous drive friction pairs was established to study the heat distribution during the mixed lubrication regime by utilizing ANSYS. Comparative analysis about different structures of oil groove, which are radial groove, circumferential groove and a combination of both groove, was finished to investigate what effects on the temperature field. The results show that separator disk has the maximum temperature Tmax=215848 ℃ in the 80s engagement process. Temperature in the zone of circumferential groove, radial groove, and frictional contact zone of the friction disk are Tmax=129145 ℃,Tmax=10084 ℃，Tmax=131255 ℃, respectively. A lower temperature can be obtained relative to the single type oil groove structure in the corresponding region. Therefore, the composite structure of oil groove has a better cooling effect, which is an ideal form of oil groove. These results have a important significance for design of friction disk.