In order to study the effect of different straw returning treatments on the yield of corn、soil water、the growth characteristics of spring corn and the photosynthetic characteristics on key growth period, a field experiment was conducted in the area of southern Ningxia.The experiment of straw returning consists 3 levels which is 3000 kg/hm²(L), 6000 kg/hm²(M),9000 kg/hm²(H)for wheat straw and 4500 kg/hm²(L), 9000 kg/hm²(M), 13500 kg/hm²(H)for corn straw. The control treatment has no straw returning. There is three times of every treatment.With the completely randomized block arrangement, straw is chopped at the length about 5cm and is uniform buried in the soil about 25cm layer. The results show that, the soil water storage of 0-200cm soil layer significantly increased,which enhanced 30.17mm, 31.13 mm, 32.83 mm respectively follow the amount of straw returning from high to low compared to CK. Compared with CK, the maize height, the stem diameter and leaf area have significantly increased(P<0.05).The photosynthetic rate and transpiration rate of corn leaf on different straw returning treatments that follow the amount of straw returning from high to low is in sustainable high level during 12:00-15:00 a day, compared with CK,the photosynthetic rate enhanced 6.52, 3.74, 3.20μmol · m^-2 · s^-1 respectively, the transpiration rate increased 2.08, 1.63, 0.72μmol · m^-2 · s^-1 respectively(P<0.05). Follow the amount of straw returning from high to low, compared with CK,grain yield of corn increased 58.3%, 36.7% and 5.4% respectively;WUE of corn increased 38.5％, 31％ and 0.9％respectively. The results of experiment from 2007-2009 showed that straw returning treatments in the area of southern Ningxia can increase WUE and the ability of soil water storage, promote the photosynthesis of corn, and then increases the yield of corn. The daily variation regularity of the photosynthetic rate and the transpiration rate is different on different soil moisture. The main limiting factor is water deficit of soil for the photosynthesis of crop in the arid area of Ningxia Province.