To address the problems of a long development period, high risk and high cost, the investment casting process and microstructure properties of large component reduction parts of ZTi60 titanium alloy were studied to provide technical support and test verification for the process design and optimization of large components. On the basis of the characteristics of the ZTi60 alloy, the casting process parameters of the reduced parts were designed, and the pouring system was designed and simulated via computer software. In addition, a hot isostatic pressing test with different parameters was carried out on a single casting test rod to determine the best hot isostatic pressing process for ZTi60 castings. The weldability of ZTi60 was tested after further increasing the difficulty of welding in the difficult position of the complex structure, and the microstructure, chemical composition and mechanical properties at different positions were tested. The results show that the casting is complete, and no obvious defects are observed on the surface of the casting. After hot isostatic pressing, the dense porosity is effectively improved, and the casting has good weldability. The chemical composition and structure of each part of the casting are uniform, whereas the grain size varies significantly. The mechanical properties are greater than the performance indices.