Based on the precipitation data of automatic tip bucket rain gauge, manual rain gauge and siphon rain gauge at Guiyang reference station from 2004 to 2020, the deviation degree of annual, monthly and daily precipitation and the difference between automatic and siphon self-recording observation hours of precipitation were analyzed. The results show that: automatic precipitation is larger than manual and siphon self-recording precipitation, and the deviation is concentrated within ±5%, and the deviation between manual and siphon self-recording precipitation is the least. The days with daily precipitation≤10mm accounted for 75.2% of the total precipitation days, and the days with abnormal deviation between automatic and manual rainfall observation accounted for 6.8%. Among the days with precipitation＞10 mm in the remaining days, the deviation between automatic and manual rainfall observation was 26.6%. The absolute difference value of automatic and siphon recording observation when the hourly precipitation deviation is over normal is highly positive correlation with hourly precipitation.