Dew is an important part of vineyard water cycle, which plays a vital role in the regulation of vineyard microclimate, and it is also a necessary condition for the germination of microbial spores. Based on the hourly meteorological observation data during the growing period of wine grape from April to October at Yinchuan agro-meteorological station from 2003 to 2020 and microclimate station of Meiyu Chateau from 2019 to 2020 and the 10-minute leaf surface temperature data from a typical winery in the same area in June 2019, the leaf temperature and air temperature were compared, firstly. When the dewing temperature was less than leaf surface temperature, the dew occurred. Taking the vineyard of Meiyu Chateau as an example, the temporal variation characteristics of dewing temperature, dewing days, dewing duration and dewing time during the growing period of grape and its influencing factors in vineyards of eastern Helan Mountain area were analyzed. The results show that the monthly dewing temperature from April to October appeared single-peak pattern in vineyards of eastern Helan Mountain area, and it reached the peak in July and the minimum in October. In the past 18 years, the monthly dewing days and duration increased gradually during the growing period, and it was the most (longest) in September, while it was the least (shortest) in April, and their inter-annual changes were obvious. Dewing could occur in the whole day, but it mainly occurred from 17:00 to next 01:00, and the range of dewing time gradually increased from April to October, it was the widest in September and the narrowest in April. The dew point temperature was significantly positive correlated with the minimum temperature and precipitation, the dewing usually occurred before and after rainfall processes and under the low minimum temperature weathers. The pests and diseases had a closely relation with dewing, so when temperature was higher in the evening in September and October, the drying and ventilating was very important for preventing pests and diseases in the vineyard.