In order to provide a quantitative method to describe artificial precipitation demand, taking Zhiyan reservoir in Lanxi as the research object, based on precipitation, runoff and water level data, the percentile threshold of monthly water level index (WLI) with different grades of the reservoir was derived from real sample probability distribution of water level, the drought index (DI) was constructed by using the entropy weight method combined with the standardized precipitation index (SPI) and the standardized streamflow index (SSI), then WLI was integrated with DI to generate the demand level index (DLI) to describe artificial precipitation demand of reservoir objectively. The temporal characteristics of WLI, DI and DLI were studied, the applicability of DLI was analyzed based on the reservoir history records, the main conclusions are as follows: (1) The constructed percentile threshold of monthly WLI with different grades was able to reflect the water shortage of the reservoir precisely in different periods of a year. (2) There was no significant change in meteorological drought from 1990 to 2019, meanwhile hydrological drought showed an increasing trend, and the increasing trend was most obvious in spring. (3) The total occurrence frequency of meteorological (hydrological) drought in summer and autumn was 33.9% (35.0%), it is higher than that （30.0% (28.3%)） in winter and spring. The occurrence frequency of severe and extreme drought in spring was the highest, and meteorological and hydrological drought accounted for 11.2% and 10.0% respectively in spring. Hydrological drought did not lag behind and had a more serious effect than meteorological drought. (4) The inter-annual distribution of DLI was similar to that of WLI, and the seasonal distribution of DLI was similar to that of DI. Artificial precipitation demand appeared more frequently and last longer in the years after 2004 than before 2004. Demand occurred most frequently in summer, accounting for 40.0%, however the demand of high and very high level occurred most frequently in spring, accounting for 14.4%. (5) The integrated DLI grades could well reflect the actual demand of the reservoir, and when DLI grade was greater than or equal to 4 for several months, the reservoir might be short of water and emergency measures required to be taken.