Complete and accurate radiation data is the precondition for using solar energy,but measured data is severely lacking. The data situation can be change effectively by establishing solar radiation area estimation model Two-stage regionalization method for solar irradiation is proposed. Clearness index and mean temperature as the first-level and second-level index of regionalization separately are employing, solar climate can be divided into 17 solar zones in China. In each zone, daily global irradiation(DGI) data of the stations without measured data will be calculated with proper regional model. Taking shaanxi province as an example to estimate province-wide 33 stations DGI data, the result shows that the amount of yearly mean DGI gradually decreases from northernmost shaanxi, northern shaanxi, guanzhong region, to southern shaanxi. The solar mapping corresponds with the principle that local latitude, climate and terrain have influence on solar radiation intensity. This result indicates that two-stage regionalization method can be used in estimating DGI.