To isolate and determine the chemical constituents from Ranunculus japonicus.Compounds were isolated by column chromatography, and identified by MS, NMR data.Nine compounds were obtained andelucidated as scoparone (1), tricin (2), protocatechuic acid (3), luteolin (4), anemonin (5), scopoletin (6), 5-hydroxy-6, 7-dimethoxyflavone (7), 5-hydroxy-7, 8-dimethoxyflavone (8), ternatolide (9), respectively.Compounds 1-9 were isolated from R. japonicus for the first time while compounds 7, 8 were separated from Ranunculus genus first time.