[Background] Soil moisture is one of the most important components of soil, it plays a critical role in the process of soil formation. Moreover, soil moisture is the main source of crop water, and is one of the most crucial parameters for the agriculture, meteorology and hydrology studies. As the important agricultural region in China, in addition to the precipitation recharge, soil moisture in the North China Plain (NCP) is also largely affected by irrigation. How to monitor and analyze surface soil moisture, drought and irrigation of a wide range using remote sensing data, has a especially important value. Studies on soil moisture and irrigation information can provide better understanding about the drought. [Methods] On the basis of 10-day's precipitation data, active microwave remote sensing inversion data -soil moisture index (SWI) data, combined with geo-statistical analysis methods, the spatial and temporal variation of surface soil moisture under precipitation drought in the NCP was analyzed and irrigation information in the main growing season of winter wheat was extracted by the method of spatial overlay analysis. [Results] 1) There were some differences in the amount and distribution of precipitation between 1999 and 1993 2002. Precipitation in June, July and August of 1999 was 50 mm lower than the average of 10 years (1993 2002), precipitation in September and October of 1999 was a little higher than the average of 10 years (1993 2002); precipitation in 1999 was more evenly distributed than annual average of 1993 2002. Precipitation in the NCP in 1999 was 140 mm less than the average of 10 years (1993 2002). 2) The change of soil moisture was consistent with the change of precipitation, which had regular fluctuation. The SWI in 1999 was lower than the average of 10 years (1993 2002), especially from March to September, which was consistent with variation of precipitation; the SWI decreased remarkably in spring and summer, which caused the soil drought to some extent. The differences of SWI between 1999 and 1993 2002 were different in different regions; the differences of soil moisture content in different stages was significant in the same area. 3) Most areas in the NCP in 1999 were irrigated in different degrees in the main growing season of winter wheat; the irrigation times in the middle part was the least, and there existed two or three rounds of irrigation in the northern and southern parts, which accounted approximately 65% of the total study area. The irrigation cells were 79.69% same with extracted result using land use data in 2000. [Conclusions] The decrease of precipitation in 1999 had an effect on variation of SWI. The soil moisture in 1999 decreased, which was consistent with the change of precipitation, indicating the arid characteristic of soil. There existed different degrees of irrigation in the NCP in 1999. The study results and methods may provide references for the agricultural drought monitoring based on remote sensing.