Abstract:Abstract：To developing a certified reference material（CRM）of ursolic acid according to the technical requirements of GB/T 15000.3-2008 ＜CRM General and Statistical Principle for Certification＞.Ursolic acid samples were obtained by means of macroporous resin，silica gel chromatography，and recrystallization from dried fruit of Crataegus pinnatifida Bge.，and their structures were confirmed by ultraviolet spectrum，infrared spectrum，mass spectrum and nuclear magnetic resonance spectrum.Ursolic acid samples were analyzed by thin layer chromatography，thermo-gravimetric and high performance liquid chromatography（HPLC）analysis technology.The ursolic acid samples were divided into bottles for homogeneity test，stability test，and cooperative certification by eight laboratories.The results showed that the homogeneity of ursolic acid samples were excellent，with good stability within 24 months at 0-4 ℃.The certified value of the reference material of ursolic acid was 99.80%with the expanded uncertainty of 0.18%in confidence coefficient of 95%.The reference material of ursolic acid was successfully developed.It was conformed to the technical requirement of GB/T 15000.3-2008 and could be traceable.The CRM can be used in the content determination and testing method validation of ursolic acid related products.