Abstract: This study aims to explore how nutrient application influences population dynamic and yield of wheat in wheat/watermelon/maize intercropping system, and to provide a scientific basis for establishing high yield and high efficiency cropping system of the intercropping wheat. The current study is a single factor randomized block design of field experiment, and includes two fertilizer treatments: farmers conventional (Con) and nutrient optimal management (Opt). From the beginning of the re- greening stage, we monitored the dynamic changes of the tiller number, panicles number, and flower number of the intercropping wheat in both border rows and inner rows under the two fertilizer treatments. At the harvest stage, we collected the data of final biomass, yield and yield component. The results revealed that the nutrient optimal management significantly increased the number of effective tillers, the ears and the flowers of the intercropped wheat in the border rows and the inner rows, and augmented the proportion of the ear-bearing tiller and therefore the ear number per m2 area. At the same time, the nutrient optimal management enhanced the border-row advantage of the intercropping wheat and increased wheat yield by 11.8% and the harvest index by 16.7%, as compared with the farmer conventional management. It is concluded that in the wheat/watermelon/maize system, the optimal nutrient management regulates the interspecific interaction and increases the harvest index of the plants in the border rows, empowering the intercropping wheat to establish high- yield population, thus to improve the intercropping advantage.