The life of solid-lubricated bearings is closely related to load. A device is developed to test the natural frequency of shaft system. The correlation between radial load which is caused by bearing pedestal misalignment and natural frequency of solid-lubricated shaft systems was researched on this test rig. The natural frequency data of shaft systems changing with radial load was analyzed. The results show that the natural frequency of shaft systems increases with the rising radial load; the correlation between radial load and natural frequency presents a power function. The radial load of solid-lubricated shaft system can be obtained by testing the natural frequency. The relative error between calculated value and experimental value of radial load is not more than 7%.