OBJECTIVE To study the effect of different proportion compatibility of Astragali Radix and Chuanxiong Rhizoma on the extraction kinetics of flavonoids. METHODS The content determination method of flavonoids(with rutin as the control substance) was established, and the concentrations of flavonoids in the extracts of Astragali Radix membranicum and Chuanxiong Rhizoma in different proportions(1∶1, 1∶2, 1∶3, 1∶4, 1∶5, 2∶1, 3∶1, 4∶1, 5∶1) were determined dynamically within 2 h, respectively. The extraction kinetics model was established according to Feck's first diffusion law. The extraction rate constant was calculated and the difference of dissolution kinetics was compared. RESULTS The compatibility of different proportions of Astragali Radix and Chuanxiong Rhizoma had significant effects on the extraction rate and concentration of flavonoids. The extraction kinetics models of flavonoids were consistent with the characteristics of the first-order kinetic equation. The extraction rate was the fastest when Astragali Radix ∶ Chuanxiong Rhizoma was 3∶1, the extraction rate was the slowest when Chuanxiong Rhizoma∶ Astragali Radix was 2∶1. The equilibrium concentration of flavonoids was the highest when Chuanxiong Rhizoma∶ Astragali Radix was 3∶1, when the ratio of Astragali Radix∶Chuanxiong Rhizoma was 5∶1, it was the lowest. CONCLUSION The compatibility of different proportions of Astragali Radix and Chuanxiong Rhizoma has a significant effect on the extraction rate and concentration of flavonoids.