The invention provides a method for compensating a cutting error of a hard-brittle material thin-walled component. The method comprises the steps of firstly building a cutting force model for cutting a material of the thin-walled component, then calculating a cutting force according to the actual radial cutting depth, solving the deformation of each discrete position in finite element analysis software by taking the actual cutting force as a load value, and finally generating a numerical control program with error compensation by taking the deformation as an error compensation value. Compared with the existing thin-walled component machining error compensation method, the method provided by the invention is higher in compensation accuracy and higher in calculation efficiency.