Salvia miltiorrhiza Bunge (Lamiaceae) root, generally called Danshen, is an important herb in Chinese medicine widely used for treatment of various diseases. Phenolic acids in S. miltiorrhiza, as important effective compounds, have become a new research focus in plant secondary metabolism in recent years. This review summarizes the recent advances in the regulation of water-soluble phenolic acid biosynthesis in S. miltiorrhiza via regulators at molecular level, such as the phenylalanine ammonia-lyase gene (PAL), cinnamic acid 4-hydroxylase gene (C4H), 4-coumarate-CoA ligase gene (4CL), tyrosine aminotransferase gene (TAT), 4-hydroxyphenylpyruvate reductase gene (HPPR), 4-hydroxyphenylpyruvated dioxygenase gene (HPPD), hydroxycinnamoyl-CoA:hydroxyphenyllactate hydroxycinnamoyl transferase-like gene (RAS-like), and v-myb avian myeloblastosis viral oncogene homolog 4 gene (MYB4), and production of anthocyanin pigmentation 1 gene (AtPAP1), and via regulators at cell level, such as methyl jasmonate, salicylic acid, abscisic acid, polyamines, metal ions, hydrogen peroxide (H2O2), ultraviolet-B radiation, and yeast elicitor.