Abstract: According to the "temperature criterion" of modeling test, the constancy of temperature of sample should be basically kept as the load and linear velocity increase. Because of the low heat conductivity of solid lubricants, controlling temperature raising is the key for fortified test. The fortified test device for solid lubricants must meet the following re-quirments: a. The load and linear velocity can be selected in a larger range; b. The plane contact form of sample is adoptted; The sample temperature can be controlled during the test. The authors improved the original design of the four-ball tester by changing the point contact form into plane contact and adding a cooling system, so the lower part of lower sample could be immersed in a cyclic cooling liquid during relative sliding, therefore the temperature raising problem was effictively solved under high-speed and heavy load. The test results showed that this kind of device has good sensitivity and repeatability for different samples.