Objective To study the chemical constituents of Salvia miltiorrhiza f. alba Methods The compounds were isolated by chromatographic techniques and their structures were elucidated by spectroscopic analysis. Results Four compounds were obtained from the plant and identified as 8, 9-dihydro-1, 6-dimethylfuro [3, 2-c] naphtha [2, 1-e] oxepine-10, 12-dione (Ⅰ), tanshindiol C (Ⅱ), salviolone (Ⅲ), 1, 2, 6, 7, 8, 9-hexahydro-1, 6, 6-trimethyl-3, 11-dioxanaphtho [2, 1-e] azulene-10, 12-dione (Ⅳ). Conclusion Compound Ⅰ is a new one, named salmilalbanone (8, 9-dihydro-1, 6-dimethylfuro [3, 2-c] naphtha [2, 1-e] oxepine-10, 12-dione), while compounds Ⅱ—Ⅳ are isolated from the plant for the first time.