In order to improve the qualification rate of gas turbine hollow turbine blades, non-destructive testing technologies such as X-ray computed tomography (CT), three-dimensional scanning (3D) and ultrasound were used to carry out dimensional measurement of turbine blades in key stages of investment casting, and the whole process of ceramic core, wax mold, mold shell and blade castings was realized. The results show that the CT technology can meet the measurement accuracy requirements of ceramic core and wax mold, and is further applied to the measurement of mold shell size. In addition, the dimensional accuracy of ceramic core, wax mold and mold shell, inner cavity and wall thickness can be detected and evaluated by using CT. The dimensional measurement method of the whole process of hollow turbine blade preparation established in this study provides strong data support for ensuring the preparation of hollow turbine blades and improving the qualified rate of large-size hollow turbine blade precision casting products.