Abstract: Field experiment was conducted to study the effect of potassium (K) nutrition on dry matter and nutrient accumulation and distribution under three K levels (K2O 0, 113 and 225 kg/ha）at reproductive stage of maize to explore the relationship between K nutrition and grain formation in maize. Results indicated that maize yield was significantly increased by K application. Both the maximum and average dry matter accumulation rate was accelerated, and the maximum dry matter accumulation rate occurred early by K application. The distribution proportion of dry matter in different organs varied distinctly. Dry matter, N and P in grain was mainly translocated from spike, and K in grain was mainly translocated from leaves. The contribution percentage of grain nutrient absorption to the whole plant at maturity was 50.3%–57.1%，59.6%–67.2%, and 14.0%–33.3% for N, P and K, respectively. K application could not only increase the distribution proportion of dry matter, N, P, and K nutrition to grain, but also enhance their translocation rates. The maximum N translocation rates of 45.7% was obtained by K1 treatment, while the maximum dry matter, P and K translocation rate of 7.4%, 62.6% and 22.4% was achieved by K2 treatment. 54.5%–60.6% of N, 56.0%–85.8% of P and 52.4%–100.0% of K in grain relied on nutrient translocation from vegetative parts.