The intermediate casing is an important component in aero-engine. Investment casting with high dimensional accuracy, controllable metallurgical quality, and characteristics of integral forming is currently the most widely used special casting method. Shell making is a key process in investment casting. Reasonable control and adjustment to process parameters during shell making can greatly reduce the rejectrate. This study applied joint arm scanning to observe partial deformation of wax patterns, studied the influence of different parameters on the surface quality of wax patterns through pouring experiments. The technical challenges of investment casting for titanium alloy intermediate casings were analyzed, the influence of physical parameters on casting quality was introduced, revealing the phenomena and mechanisms of interactions between different parameters. The results indicate that the influence of physical parameters on casting quality is complex and interrelated. For large, thin-walled and complex structural parts, using higher-strength mold materials to make wax pattens can reduce surface shrinkage and deformation of the wax molds. Surface flow mark defects on wax molds can be eliminated by adjusting wax injection parameters, but this may introduce other defects. Increasing the temperature can reduce the size of the wax pattens and may exacerbate deformation in complex and unstable structures.