Based on the hourly European Centre for Medium-Range Weather Forecasts (ECMWF) fifth-generation global atmospheric reanalysis (ERA5) and the hourly precipitation product from the CMA multi-source Precipitation Analysis System(CMPAS-hourly) from January 1 to December 31, 2018, the temporal and spatial distributions of water vapor,hydrometeors and cloud water resources in Guangdong in 2018 were evaluated by using the proposed evaluation method of air water substances based on the atmospheric water material balance equation. In 2018, the water vapor precipitation efficiency in Guangdong was 5.1%, and the hydrometeors precipitation efficiency was 89.6%; both water vapor and hydrometeors were net output by taking Guangdong Province as a whole. For the spatial variation, the total water vapor gradually decreased from southwest to northeast, the high value area of total amount of hydrometeors located on the south slope of the Yunwu Mountain, the Tianlu Mountain in western Guangdong and the Lianhua Mountain in eastern Guangdong and the total amount of cloud water resources gradually decreased from northern mountainous areas to coastal areas, and the precipitation efficiency of hydrometeors gradually decreased from coastal areas to northern mountainous areas. For the temporal variation, the total amount of water vapor was largest in summer, the total amount of hydrometeor was largest in the second half of August and the first half of September, and the total amount of cloud water resources in non-flood season were higher than those in flood season. The variations of water vapor and cloud water resources in monthly scale were larger than those in weather scale, and the variation of hydrometeors in weather scale was larger than that in monthly scale.