Abstract: Cotton is one of the most important crops in saline-alkaline land in the Yellow River delta. The cottonseed, cotton straw and waste cotton were returned to the field in this study in Maotuo, Lijin Country. Meanwhile, the physic-chemical and biological properties were investigated in order to discuss the effect of different wastes, including cottonseed, cotton straw and waste cotton returning to the field on the soil quality of saline-alkaline land. The author expected to provide more scientific materials on improvement and utilization of coastal saline-alkaline land by this study. The results showed that: soil bulk density decreased and soil porosity and field capacity increased in cottonseed treatment (CT), cotton straw treatment (CST) and waste cotton treatment (WCT) compared to control treatment. Meanwhile, pH and the content of soil salt decreased, but cation exchange capacity (CEC) and the content of soil organic matter (SOM) increased. The effect of improvement of saline-alkaline land were in the order: CT>CST>WCT. Compared to control treatment, the quantity of microorganism, yield of cotton and soil respiration intensity increased in the order: CT>CST>WCT. However, the effects of improvement of saline-alkaline land decreased with soil depth. It suggests that the cottonseed is better rather than cotton straw and cotton waste in improvement of saline-alkaline land, and then is the cotton straw.