Geostatistics focuses on spatial variance analysis. By analyzing meteorological data relating to Henan province from 1950 to 2000, we calculated the photosynthetically active radiation (PAR) of tobacco at each growth stage, and studied the spatial variability and distribution characteristics of PAR by using geostatistics in a GIS platform. The PAR data fitted well with a normal distribution, correlating with the current hypothesis for geostatistics. The coefficient of variation (CV) of PAR for the tobacco growth stages was highest (i.e. 9.61%) in May, while it was lowest (i.e. 3.92%) in July. The PAR during tobacco growth fitted well with the Gaussian model, with a spatial dependence distance of 1719300.00 m. The C₀/sill was 21.36%, indicating a strong spatial correlation. A PAR range of 987-1024 MJ/m², accounting for 19.37% of the whole province, occurred mainly in Nanyang City, Xinyang City, Luoyang City, Sanmenxia City, and Pingdingshan City; a PAR range of 1024-1060 MJ/m², 34.50% of the whole province, occurred mainly in Sanmenxia City, Luoyang City, Pingdingshan City, Nanyang City, Zhumadian City, Xinyang City, and Luohe City; a PAR range of 1060-1097 MJ/m², 19.98% of the whole province, occurred mainly in Jiyuan City, Luoyang City, Zhengzhou City, Pingdingshan City, Xuchang City, Luohe City, Zhumadian City, Zhoukou City, Shangqiu City, Sanmenxia City, Xinxiang City, and Anyang City; a PAR range of 1097-1133 MJ/m², 26.15% of the whole province, occurred mainly in Kaifeng City, Hebi City, Jiaozuo City, Xinxiang City, Anyang City, Puyang City, Zhengzhou City, Jiyuang City, and Shangqiu City; and a PAR range of 1133-1170 MJ/m², 3.02% of the whole province, occurred mainly in Puyang City and Anyang City. Our research showed that large-scale spatial variance of PAR could be analyzed effectively with geostatistics and GIS, thus providing precise data for the management and quality/quantity improvement of field crops.