In this study the principal component analysis (PCA) and geographically weighted regression (GWR) are combined to estimate the spatial distribution of water requirement of the winter wheat in North China while the effect of the macro-and micro-topographic as well as the meteorological factors on the crop water requirement is taking into account. The spatial distribution characteristic of the water requirement of the winter wheat in North China and its formation are analyzed based on the spatial variation of the main affecting factors and the regression coefficients. The findings reveal that the collinearity can be effectively removed when PCA is applied to process all of the affecting factors. The regression coefficients of GWR displayed a strong variability in space, which can better explain the spatial differences of the effect of the affecting factors on the crop water requirement. The evaluation index of the proposed method in this study is more efficient than the widely used Kriging method. Besides, it could clearly show the effect of those affecting factors in different spatial locations on the crop water requirement and provide more detailed information on the region where those factors suddenly change. To sum up, it is of great reference significance for the estimation of the regional crop water requirement. Crop water requirement is an important parameter in the calculation of the equilibrium of water and soil resources and the design, operation, and management of the irrigation projects [1]. Many methods of measuring and estimating crop water requirement have been proposed in China and foreign countries [2][3][4][5]. Although these methods exhibit accuracy in their respective applications to some extent, what is obtained when they are used are mostly point data, which can neither be used directly for other points nor as the average data of a large area [6]. Therefore, how to make full use of the data obtained from the measured points has been the focus of most studies since it is impossible to lay out as many test sites as desired [7][8][9][10][11][12]. Spatial interpolation methods now commonly used, such as inverse distance method, are simple and easy to apply. However, only the effect of the geographic coordinates are considered in those methods and the change in the spatial structure of the crop water requirement is scarcely revealed. Although adjusted geological statistics is usually applied in the estimation of crop water requirements, the sample data should meet important prerequisites [13]. When regression analysis is adopted, both the effect of macro-terrain and that of the micro-terrain factors on crop water requirement are taken into account. However, those factors are complicated and a correlation among those factors is also found [14]. The correlation contradicts the hypothesis that all of these factors are independent from traditional global regression analysis. Moreover, crop water requirements are typically regionalized variables [8] and almost spatially dependent. In most traditional s...