This study aimed to validate the agricultural drought indices derived from NOAA/AVHRR data and analyzed their uncertainties by taking Taigu County in Shanxi Province and Ji’ning County in Shandong Province for examples. The result from the analysis of relationships between drought indices and soil moisture in Taigu County shows that vegetation health index ( H), temperature condition index (T) and vegetation condition index (V) have somewhat low relations with soil moisture ( R2 is 0. 51, 0. 50, and 0. 56, respectively). Hand T have the closer relationship than normalized difference water index (W) and V. Validation using the data in J i’ning County shows that H, T and V have better relations with soil moisture (R2 is 0.97, 0.93, and 0.66, respectively). Whas a poor relation with soil moisture in the two cases. These suggest that the uncertainties in drought monitoring should be analyzed in terms of the crop planting pattern, monitoring time scale, vegetation condition and farming activity.