A pot experiment was conducted to study the effect of nitrogen (N), phosphors (P) and potassium (K) application on the yield and nutrient absorption of forage in sudangrass/ryegrass rotation which is popular in Jianghan Plain for fishing industry. The results showed that fresh forage yield in the treatment with N, P and K fertilization increased by 6.1, 10.6 and 0.6 times respectively, compared with no N, P and K treatments. The nutrient absorption amount result indicated N application received 6.9, 3.5 and 4.7 times more N, P and K amount, P application received 5.9, 23.2 and 7.3 times more N, P and K amount, and K application received 0.3, 0.7 and 7.4 times more N, P and K amount, respectively. The result suggested that N, P and K combined fertilization could improve apparent fertilizer utilizing efficiency mutually. P and K fertilization could reduce soil acidification. The soil organic matter among different treatments was not different significantly after the experiment. The soil NH₄⁺-N content in NK Treatment (no P) was obviously higher than other treatments, available P content with N fertilization was significantly lower than other treatments, and available K contents in PK and NK Treatment were significantly higher than other treatments.