Abstract: Dry and ripe seeds of Astragalus complanatus were used as explants for rapid propagation to compare the mutagenic effects of different concentrations and durations of colchicine on A. complanatus. Rapid propagation experiments showed that MS was the optimal medium for buds, while MS+6-BA 3.0 mg/L+NAA 0.5 mg/L was the optimal proliferation medium with an average proliferation coefficient of 4.5 and average plantlet height of 3.5 cm. The best rooting medium was 1/2 MS+NAA 0.05 mg/L with a root count of 4-6 and 100% rooting. Apical buds of A. complanatus were immersed in 0.1%, 0.3% and 0.5% colchicine solutions for 1, 2, 3, or 4 d. Chromosome numbers of root tip cells in the regenerated plantlets were examined and showed that treatment with 0.3% colchicine solution for 3 d was the best combination of time and concentration. The polyploid rate was up to 40%.