Abstract: Differences in soil C∶N and C∶P ratios at oasis spring wheat under regulated deficit irrigation were analyzed for two experimental years using Paired-Sample T-Test. Soil organic C balance was also analyzed which provided basic data for soil nutrient element transformation and cycling. The study was a proxy for further advances and expansion of ecological stoichiometric theory. Compared with 2007, results indicated that C∶N ratio in the 0~20 cm, 20~40 cm and 0~40 cm soil layers at field of oasis spring wheat harvested in 2008 significantly dropped by 19.0%~37.3%, 11.8%~27.9% and 17.1%~32.8%, respectively. Concurrently, C∶P ratio significantly increased by 31.9%~62.4%, 16.5%~79.1% and 33.6%~68.8%, respectively. Higher C∶N and C∶P ratios were observed under the treatments with light or medium water deficit in jointing stage, light or not water deficit in booting to heading stage, and medium or sever water deficit in filling to maturing stage. Furthermore, soil organic C content in different soil layers increased after two years of experimentation. It increased by 1.31~2.35 t(C)·hm^-2 in the 0~20 cm layer, 2.00~4.58 t(C)·hm^-2 in the 20~40 cm layer and by 2.18~3.07 t(C)·hm^-2 in the 0~40 cm layer.