The invention discloses a method for controlling the machining accuracy of large integrated thin-walled parts based on finite element analysis. The method comprises the following steps of: 1, extracting local structural features of the large integrated thin-walled part; 2, performing finite element simulative analysis on local structural features to obtain an optimized cutting technology; 3, numerically modeling a large integrated workblank, and loading an initial internal stress; 4, protocoling a tool path, namely protocoling the machining sequence of the feature structures; 5, performing simulative analysis on the integrated structure to obtain a predicted deformation result under the condition of process technology; 6, regulating and optimizing a clamp scheme to control machining deformation. The method adopts finite element simulation, can analyze and predict in advance before the actual machining of the parts, and thereby corresponding machining strategy is adjusted, machining deformation is effectively controlled, production cycle of the parts is shortened, and production cost is reduced.