Abstract: For a certain type of impeller casting with complex curved blades, an investment casting process was designed.By designing the scale of the model in sections and setting the correction of the anti-deformation process, it is ensured that the size of the mold shell matches the size of the process design. The top injection and inner runner dispersion introduction method were adopted to realize stable filling. Castings with high internal quality, surface quality and dimensional accuracy are successfully obtained by adopting the technology and measures.