A false alarm fault frequently appeared in antenna-servo system of the CINRAD/SA weather radar of Shanwei in the second half of 2011,so possible reasons for the false alarm fault were listed firstly using method of exhaustion,and then the main reason was determined using exclusive method.That is,the fault was closely related to the signal transmission channel from the antenna mount to servo system in RDA cabinet.After examining questionable nodes in the transmission channels of the alarm signal,we found that the false alarm fault might result from the interference of a burr in the temperature sensing circuit of the elevation motor.In actual operation,a filter capacitor was connected with the corresponding pin in the upper optical board to screen the interference of a burr,thereby successfully eliminating the false alarm fault in antenna-servo system of the CINRAD/SA radar of Shanwei. A false alarm fault frequently appeared in antenna-servo system of the CINRAD / SA weather radar of Shanwei in the second half of 2011, so possible reasons for the false alarm fault were listed first using method of exhaustion, and then the main reason was determined using exclusive method.That is, the fault was closely related to the signal transmission channel from the antenna mount to servo system in RDA cabinet. After the questionable nodes in the transmission channels of the alarm signal, we found that the false alarm fault might result from the interference of a burr in the temperature sensing circuit of the elevation motor.In actual operation, a filter capacitor was connected with the corresponding pin in the upper optical board to screen the interference of a burr, so successfully eliminate the false alarm fault in antenna-servo system of the CINRAD / SA radar of Shanwei.