Objective To prepare reference materials of total mercury and methyl mercury in Agaricus blazei murill.Methods Agaricus blazei murill with suitable content of total mercury and methylmercury were screening from markets. After drying， grinding， screening， homogenized and packed， the reference materials were obtained. After homogeneity and stability tests， coordinated values were determined by seven laboratories， and the uncertainties were evaluated.Results The characteristic value of total mercury was 0.586 mg/kg， and the expanded uncertainty was 0.026 mg/kg. The characteristic value of methylmercury was 0.022 7 mg/kg， and the expanded uncertainty was 0.001 5 mg/kg.Conclusion The reference material has good stability， can be used for traceability and quality control of analyzing.