The invention provides an RTCM3 data decoding method. The method comprises the steps that 1, a program is started; 2, an RTCM3 data message template file is read in; 3, whether the RTCM3 data message template file is successfully loaded is judged, if loading succeeds, the step 4 is executed, and if loading fails, the step 8 is executed; 4, verification is performed; 5, whether verification succeeds is judged, if verification succeeds, the step 6 is executed, and if verification fails, an error is output and processed, and the step 8 is executed; 6, a program file is generated; 7, an RTCM3 message coding and decoding file is automatically generated, and the step 9 is executed; 8, failure processing is performed, and the step 9 is executed; and 9, the program is ended. According to the method, a template concept is proposed, the RTCM3 data coding and decoding file is automatically generated, coding efficiency is improved, introduction of human errors is reduced, and a coding and decoding process is realized.