Abstract:Objective: The experiment was conducted to study the dynamic growth rhythm of Achyranthes bidentata under different densities. Method: The plant samples were collected to measure the growth rate of each organ. Result: Under different densities, the growing dynamic rhythm of A. bidentata were similar. The growth of main root exhibited a trend of "slow-fast-slow by stages. The increase of dry root weight was fastest during the period of 30-40 days before harvest. The dry-matter increasing rate of whole plant was fastest in the later period of branching stage. The differences of root yields among the plants growing under different densities were significant. Conclusion: For high yield and good quality, the density of planting of A. bidentata should be considered.