Early maturing cotton variety “JX0010” was used in this research as test material The effects of nitrogen concentration, density and planting period on the accumulation and distribution of cotton dry matter were studied by using the quadratic optimal regression design（311 design）The results showed that: The accumulation of dry matter accumulation of cotton single plant and reproductive organs is basically consistent with the change of “S” curve The dry matter accumulation was relatively slow in the early stage of the growth, and actually accelerated in the middle stage The dry matter accumulation at the later stage began to flatten The density is the main factor that affects the accumulation of dry matter The accumulation of dry matter of single vegetative organs increases with the increases with the increase of nitrogen fertilizer, and the delay of planting time increases first and then decreases, and decrease with increasing density The accumulation of dry matter of single plant reproductive organs increased with the increase of nitrogen and decreased with the increase of density and delay of planting time The cotton population dry matter accumulation increased with the advancement of growth period, and had biggest value in the 9th treatment (20 640 kg/hm2) and increased by 15.74%-137.48% than other treatments