The invention relates to a prestressing concrete foundation for a wind turbine generator. The prestressing concrete foundation for the wind turbine generator can effectively resist shearing force and stamping between draught fan foundation rings and a concrete foundation and spread force to more peripheral concrete areas so as to solve the problems of concrete stress concentration, concrete cracking and compression-shear failures around the draught fan foundation rings and to achieve the purpose of loading prestress. According to the technical scheme, the prestressing concrete foundation for the wind turbine generator comprises a concrete foundation, foundation steel bars embedded in the foundation, the draught fan foundation rings embedded in the top of the foundation and bottom flanges welded to the bottoms of the draught fan foundation rings. The prestressing concrete foundation for the wind turbine generator is characterized in that grouting steel rings are installed on the peripheries of the draught fan foundation rings and in the concrete foundation, and grouting pipes are preinstalled on the grouting steel rings and are brought out of the foundation. The prestressing concrete foundation for the wind turbine generator is suitable for natural foundation concrete foundations, pile foundation concrete supporting platforms and the like in the field of foundation structure projects of wind power generation.