Sugarcane (Saccharum sinensis Roxb) is an important sugar crop in China which mainly produced in subtropical and tropical region of China. Wide row spacing (120 cm) and initial slow growth rate of sugarcane offers a suitable space and resources (water, nutrition, light) niche for intercropping in sugarcane. Meanwhile, over input of nitrogenous fertilizer was also a big problem which results in soil acidification and environmental pollution. How to reduce nitrogen application and design suitable sugarcane intercropping pattern is the key techniques to make the sugarcane production more sustainable in south China. In order to explore the sugarcane fresh yield and dynamic changes in nitrogen uptake by sugarcane, soil nitrate, ammonium and microbial biomass nitrogen, a field experiments were conducted in 2010 at experimental farm of South China Agricultural University (23°08'N, 113°15'E). The experiments were the randomized block design with two levels of N fertilizer (300 kg/hm², 500 kg/hm²) and four cropping patterns (sugarcane monoculture, soybean(Glycine max L.) monoculture, sugarcane//soybean (1 ∶ 1 rows) intercropping, sugarcane//soybean (1 ∶ 2 rows) intercropping). All the treatments have three replicates, each plot (4.8×5.5 m) grows four rows of sugarcane except the soybean monoculture treatment in which grows 16 rows soybean. The results showed that sugarcane fresh yield significantly decreased in 1 ∶ 1 and 1 ∶ 2 rows intercropping systems compared to sugarcane monoculture under reduced N application (300 kg/hm²), but the LER (land equivalent ratio) of the two intercropping treatments were bigger than 1, and harvested 1.52 and 3.25 t/hm² soybean respectly. There is no significant difference between the sugarcane fresh yield of the two nitrogen application levels. Nitrogen rates and cropping patterns did not influence sugarcane's nitrogen uptake, soil nitrate and microbial biomass nitrogen when the sugarcane harvested. Soil nitrogen in the plough layer changed with crops growth, the lowest content appeared at tillering (soybean harvest) growth stage of sugarcane, soil nitrate nitrogen content was remarkably higher in sugarcane//soybean intercropping (1 ∶ 1 rows) than sole cropping in this stage. In conclusion, intercropping patterns improved the LER, reduced nitrogen application did not notably affected sugarcane fresh yield, and the soil nitrogen content in plough layer was not different in all treatments. Sugarcane//soybean intercropping under reduced nitrogen application is feasible to practice in consideration of improving the utilization rate of land and agricultural environmental protection.