Objective: To compare the dissolution quantities in vitro of ferulic acid and the analgesic effect of Rhizoma Chuanxiong by supper-micronized powder, fine powder, water extraction, alcohol extraction and double extraction. Methods: Their dissolution rates in vitro were determined by paddle stirring method, the dissolution quantities of ferulic acid in 60 min were determined by TLC-scaning, the analgesic effects were determined by torsion and hot-plate methods. Results: The dissolution quantities of ferulic acid were respectively: supper-micronized powder (0.645?0.008)mg, fine powder (0.359?0.005)mg, water extraction (0.220?0.004)mg, alcohol extraction (0.526?0.007)mg, double extraction (0.061?0.003)mg. The analgesic effect of supper-micronized powder of Rhizoma Chuanxiong was the best. Conclusion: The supper-micronized powder of Chuanxiong improved the dissolution quantity of active components and improved the potency.