Using artificial and automatic acid rain observation data from National Basic Meteorological Station of Xichang in 2021, the precipitation sampling deviation and completeness, the accuracy and consistency of measured data, the fault rates of the hardware and software communications of type 1 TCYII acid rain automatic observation system and artificial system were compared and analyzed. The results show that, under normal circumstances, the data completeness, accuracy and consistency of the two systems are good. The acid rain automatic observation system has certain advantages in sampling method and sample preservation, which can ensure that the observation data is closer to the value of natural rainwater and to the real situation. The automatic observation system has problems of monorail operation, and its manual operation and some accessories need to be optimized and improved by the manufacturer. The higher-level authorities still need to further clarify the operation methods for setting the system’s measurement thresholds, for peculiar situations such as missing records, empty records and excessive records that occur during sampling.