In order to study thermal instability phenomenon of cylindrical roller bearings in a spacecraft,an electric spindle driven and cantilever supported bearing test rig was designed.A pair of supported bearings with one end fixed and another end freely traveling was used for the rig to adapt the thermal transform of the spindle.Hydraulic loading was adopted as source of test bearing’s static load.Oil injection toward end face was adopted to achieve lubrication and heating function.PRO/MECHANICA software was used to analyze the heat transfer and its influence on spindle temperature distribution in the heating test with E2224HT cylindrical roller bearings as a test object.Multirelated factors influencing the thermal characteristics of the test bearing were considered via further orthogonal experiments.Experimental results indicate that the rotating speed is the key factor to influence the maximum temperature of the test bearing,in addition,rotating speed and load have remarkable effect on the temperature change rate,and the speed effect is more notable. 