Abstract: Drought is a common and serious natural disaster,and it seriously effects the agricultural production in China.This paper takes Henan Province,China,as an example,and uses MODIS products MOD13Q1 to obtain vegetation index (NDVI,EVI),and MODIS11A2 to obtain the surface temperature (Ts) data,then constructs the Vegetation Supply Water Index (VSWI_N,VSWI_E) which indicates the regional drought characteristics.Then,they are compared with the Standardized Precipitation Index (SPI) that is calculated by the data from 16 national weather stations in Henan province at different time scales form 2000 to 2016.Finally the comparison and analysis are carried out.The result shows that VSWI_E is more suitable than VSWI_N for drought study in Henan Province.The correlations between VSWI and the SPI value at 3 and 12 months scales are higher and more suitable for the drought study of Henan Province.In terms of time,the drought frequency of Henan Province is high,and the spring and summer drought frequencies are 0.33 and 0.30 respectively.The overall drought trend is even more obvious.The worst spring drought happened in 2000,and the worst summer drought occurred in 2014.From the view of space,the drought degree in the north and west of Henan Province is more serious than that in southern Henan.This study reveals the development characteristics of drought in Henan,and provides some useful information for the monitoring and early-warning of drought in Henan.

Key words: VSWI, SPI, monitoring drought, Henan Province