With the simulated runoff data at the 5.km×5.km grid cells from 1981 to 2020 based on the VIC model and the confluence model, a long-term and grid SRDI (standardized runoff drought index) was constructed. Then, the spatiotemporal evolution characteristics of drought in the Pearl River Basin were analyzed. The results show that: the grid SRDI based on simulated runoff can better simulate the spatiotemporal variation of drought in the Pearl River Basin; the temporal evolution characteristics of drought are obvious, hydrological drought mainly occurs in summer, and a large-scale drought may probably occur in autumn; on the seasonal scale, it is possible that extreme drought occurs all the year around; spatially speaking, the hydrological droughts in the Pearl River Basin present a transitional distribution from the east with high-frequency, to the west with long-duration and high-intensity.