Abstract: This article mainly discusses the error control technology for CNC machining of large hydraulic turbine blades and discs, focusing on studying the model of part machining contour error caused by geometric errors, nonlinear errors, and other factors of CNC machine tools, and proposing corresponding accuracy control methods and compensation measures.This technology has been successfully used in the production and manufacturing of bladed disc parts, and the machining accuracy of the parts has been significantly improved.