Abstract: Experiment about spring wheat and green manure(Melilotus suaveolens,Rape,Oil sun flowers,soybean)on the continous cropping cotton fields, study their biomass ,plant nutrient content and the effect of green manure application on soil nutrients in cotton fields.The results showed that: biomass in the Melilotus suaveolens is the highest in four green manure; after pressed four green manure in the Green the cotton fields, soil organic matter,nutrients are available certain influence; after Melilotus suaveolens and soybean pressed in the soil,organic matter increased by 8.58% and 1.01%;four green manure pressed in the soil available nitrogen increased by0.30%-5.96%,except soybean, the soil available potassium of the other three dealt is 1.08 times that of the control; the role of rich potassium in Rape and Oil sun flowers are even more significant .This experiment researched spring wheat mutiple Melilotus suaveolens is a relatively good crop rotation.