Transesterification of Chinese tallow kernel oil was studied in the presence of heterogeneous solid catalysts prepared from waste slag derived from a metal magnesium plant. The series of catalysts showed the high activity for transesterification to be over 96% fatty acid methyl ester. The advantages of those catalysts include their simplicity of their preparation and low cost of the raw materials. Preparation of biodiesel with Chinese tallow kernel oil has a bright future in China.