In order to master the occurrence regularity of winter wheat late frost injury in He nan Province，and take timely measures for disaster prevention and reduction，this paper firstly selects these risk evaluation indexes including the winter wheat late frost harmful chilling accumulation and frequency (risk) ，the planting area of winter wheat (exposure) ， and the ratio of irrigated and tillable field area，well number per unit area (vulnerability)to establish risk evaluation system，and then determines the weight of winter wheat late frost risk evaluation index by using analytic hierarchy process，finally the winter wheat late frost freeze risk evaluation model was built． Based on 1984 － 2013 climate data， the late frost of winter wheat in He nan Province was evaluated by using the risk assessment model，and according to the winter wheat late frost risk evaluation model for grid computing in ArcGIS，the winter wheat late frost risk zoning map in He nan Province was obtained． The results show that the late frost risk index was high which ranged from 0． 289 to 0． 483 in the eastern Shangqiu，Zhoukou，Luohe，most part of Zhumadian，some part of Xinyang and Nanyang，while in most of Sanmenxia， Luoyang，Jiyuan，Jiaozuo，Zhengzhou，Anyang，Hebi，Xinxiang and other areas the late frost risk index was less than 0．123． Finally， the correlation analysis was carried out between the late frost index caculated by using historical statistical data and the results of this study，and the correlation coefficient was 0．78，which showed that the winter wheat late frost risk zoning results in He nan Province were consistent with the historical statistics．