Abstract: The accuracy of measurement results of acid rain water samples is very important for the study of acid rain spatial and temporal distribution, treatment and prevention. Extreme value method and comparison method of quality control currently used in Jinsha atmospheric background station cannot ensure the accuracy of acid rain observation data. Combining with the assessment work of Jinsha atmospheric base station for years, we analyzed the purpose and criteria of acid rain sample assessment, the classification of measurement errors and the sources of acid rain measurement errors, and introduced the quality control method of acid rain measurement, which is conducive to improving the quality of acid rain observation at weather stations.