Abstract: Based on the main influencing factors and process parameter range that affect the filling ability of molten metal in lost foam casting, the influence of different sample shapes and sizes on the filling distance was studied.On this basis, a testing method and test samples for the filling ability of molten metal in lost foam casting were established, and corresponding sample forming molds were designed. The experimental results indicate that this method can be used to test the filling ability of molten metal in lost foam casting of cast iron parts, and has a good effect on studying the filling characteristics of lost foam casting and optimizing the production process of lost foam casting.