Abstract: When functionally gradient material（FGM） is prepared by extrusion method, Bubbles and agglomerations are inevitable in the preparation of water-based paste. When the bubbles break and agglomerates decompose, the extrusion process will be unstable and the quality of formed parts will be poor. Using the minimum variance adaptive controller to control the extrusion pressure of different materials in the extrusion process can effectively reduce this effect, but this control method is difficult to realize the preparation of arbitrary "gradient" FGM materials. A proportional controller combining extrusion speed control and extrusion pressure control is designed to realize the preparation of any gradient FGM material, while reducing the impact of bubbles and lumps. The effectiveness of the proportional controller is verified by experiments.