Based on the day and night precipitation data of 64 stations in the Loess Plateau of China from 1961 to 2020 from the National Meteorological Information Center， the Loess Plateau is divided into two regions （monsoon region and westerly region）.The variation characteristics of daytime and nighttime precipitation days and precipitation in the two regions in two seasons （wet-season and dry-season） were analyzed using methods such as linear trend and t test.The main conclusions are as follows： There are significant seasonal differences in daytime and nighttime precipitation between the monsoon region and the westerly region of the Loess Plateau.The number of daytime and nighttime precipitation days in the wet-season （May-September） in the monsoon region accounts for 60% of the whole year， and the precipitation is more than 75%.In the westerly region， the proportion of daytime and nighttime precipitation in the whole year is nearly 70%， and the precipitation is more than 80%.The Loess Plateau tends to get wet in the westerly area and dry in the monsoon area.Among them， the most prominent feature is that in the westerly region， The number of stations which measured increase in daytime accounts for 77.8% of the total.in the wet-season， and more than 50% in the dry-season.In the monsoon area， the number of stations in daytime and nighttime which measured decrease in precipitation days and precipitation account for more than 80% and 50% respectively in the wet-season， and more than 95% and 80% respectively in the dry-season.