The article mainly analyzes the measurement 〖JP2〗errors based on the structural principle of the SL31〖JP〗 double tipping bucket rainfall sensor. According to the different water capacities of the sensor tipping bucket, the precipitation errors are compared by a precipitation simulation experiment. The purpose is to obtain the proper proportional relationship between the upper bucket and the metering bucket when measuring 10 mm precipitation under the heavy and light rainfall intensities (1 mm/min and 4 mm/min). Therefore, the measurement errors are minimized and the measurement error consistency is the best under the two rain intensities. The results show that for the 10 mm precipitation measurement, the most appropriate ratio of the number of times the upper bucket turned to that of the measuring bucket turned is 9∶10. The determination of the proportional relationship provides a technical reference and basis for the outoftolerance adjustment of the double tipping bucket rainfall sensor, and provides guarantees for the accuracy and reliability of the rainfall observation data.