The purpose of the experiment is to find out the variation of the slip rates of tractors on different types of roads on which they often run, such as cement road, gravel road, dirt road. The running speed of the tractor was measured by GPS, Doppler radar and the minimum wheel speed method, and the speed of the driving wheel of the tractor was measured by the encoders. PCI1740 data acquisition card was used to collect sensors data, and then the graphical programming software Labview was used to display and store real-time data. The experiment was carried out on different roads with different running speeds of the tractor. The test results showed that the minimum degree of slippage occurred on the cement road while the largest slippery occurred on dirt road. When the tractor was running at a low speed (first gear, second gear), the tractor′s slip rate was 9.0%-13.6%. When the tractor was running at a high speed (third gear, fourth gear), the slip rate was 3.26%-6.27%. The GPS test results were not affected by the road conditions, and the radar method was suitable for the good road conditions, and the minimum wheel speed method was suitable when the tractor was running at a high speed. The tractor′s slip degree decreased with the increase of the speed of the tractor.