According to the field experiences from the maintenance practice in an automatic weather station in recent years, various kinds of common faults for SL3 1 tilting rain sensors are classifieds, based on the relevant technical requirements and design principles of other similar instruments.Combined with the specific circumstances of the annual maximum precipitation in Tibet, the improvement measures and suggestions for the water intake, electrical, and base components are put forward, to reduce the equipment failure frequency and improve the accuracy of observation. In order to ensure the calibration of instruments according with the accuracy and comparative requirements, the problems encountered in the field maintenance of equipment are summarized, and a self made special equipment box for storing core components is introduced, to improve the efficiency of field maintenance.