Abstract: By means of the analysis of forces supplying on every roller in cylindrical roller bearing,the feasible method to compute the thermal value under different loads and velocity is investigated.The formula used to calculate accurately thermal value are obtained.And with this method the thermal value of every roller of a specific bearing is calculated.Then the thermal value taken as boundary condition is used to simulate the distribution of temperature field of the bearing system.A fact is discovered that the distribution of temperature field of the bearing coincides primarily with the reality.It is confirmed that the established method is viable to compute the thermal value and temperature field of cylindrical roller bearing.