Abstract: Salvianolic acid B, an active compound, is the most abundant phenolic acid in Salvia miltiorrhiza Beg.. It is unstable in aqueous solution. According to the reports, salvianolic acid B is more stable in the solution with weak acid, low temperature and low ionic strength. And adding some antioxidants or salvianolic acid ingredients can reduce the degradation rate of salvianolic acid B. Hydrolysis of ester bonds, opening of furan rings and decarboxylation are the main degradation reactions of salvianolic acid B in aqueous solution, and these reactions can produce products, such as danshensu, lithospermic acid and its isomers, protocatechuic aldehyde, salvianolic acid A, C, D, E, F, etc. In this review, the advances of pathway and influence factors of salvianolic acid B degradation were summarized.