Abstract: Density regulation plays a vital role in maintaining forest trees nutrient balance and improving forest land productivity. Five kinds of density regulation （CK: 100,000 culms hm⁻², D1: 40,000 culms hm⁻², D2: 50,000 culms hm⁻², D3: 60,000 culms hm⁻², and D4: 70,000 culms hm⁻²） were set in a pure forest of Chimonobambusa pachystachys in Gulin County, Sichuan Province. The Chimonobambusa pachystachys leaf nitrogen, phosphorus content, and bamboo shoot yield and their correlation were studied under five different densities. The results showed that the ratio of nitrogen to phosphorus in the leaves of Chimonobambusa pachystachys under all treatments was greater than 16, indicating that the growth of Chimonobambusa pachystachys was easily restricted by phosphorus. D1 and D2 treatments significantly reduced leaf nitrogen content, D3 and D4 treatments significantly increased leaf phosphorus content but significantly reduced leaf nitrogen to phosphorus ratio and alleviated the phosphorus limitation. D3 treatment significantly increased Chimonobambusa pachystachys bamboo shoot yield by 21.60%, and the bamboo shoot yield was 3690.05 kg hm⁻² a⁻¹. The yield of bamboo shoots was significantly positively correlated with leaf nitrogen and phosphorus content, and was significantly negatively correlated with leaf nitrogen and phosphorus ratio. The results indicated that the growth of Chimonobambusa pachystachys in the study area was easily restricted by phosphorus, so it was appropriate to apply phosphorus fertilizer to bamboo forest. Density regulation significantly changed the nitrogen and phosphorus nutrient characteristics in the leaves of Chimonobambusa pachystachys. When the density of standing bamboos in the study area was reserved at 60,000 hm⁻², a higher bamboo shoot yield could be obtained.