Abstract: Based on the information poor theory, the relationship between the starting friction torque of the slewing bearing and the load was discussed to reveal nonlinear evolution characteristics of the estimated true value, fluctuation range, information entropy, variation coefficient, and probability density function of the starting friction torque. In the simulated experiment, two different slewing bearings were adopted, the load was changed five times for each bearing, the starting friction torques of six points which were evenly distribution on the surface of the inner ring were measured simultaneously, and variation analysis of the test data was made. The test result showed that with the rise of the load, the estimated true value nonlinearly increased and the variation coefficient nonlinearly decreased in view of the overall situations, at which there was a sensitive spot where the variation coefficient increased abnormally. This indicated that the starting friction torque of the slewing bearing had the uncertainty of the variable and the polytropy of the function. The findings provide a reference for analyzing the measuring system and improving the bearing performance.