The invention relates to a method for comprehensively treating 
saline alkali soil. The method is characterized in that a method in which physical improvement and biological improvement are combined is used for treatment. According to the physical improvement, project land parcels for treating the 
saline alkali soil are constructed, a road is constructed in the middle, a 
ditch is constructed on one side of the road and provided with multiple branches for 
irrigation of all the land parcels, a salt and alkali discharging 
branch canal is arranged beside the 
land parcel on the outermost edge, and the 
branch canal is converged to a main salt and alkali discharging canal. The biological improvement includes 
fertilizer preparing, mellow soil 
insect luring, soil loosening 
insect killing, planting of any one of 
saline-alkaline resistant 
zizania aquatica, corn, 
astragalus membranaceus, liquorice and chrysanthemum in the next year and 
crop rotation of 
crop of the previous year in the third year. Project facility design is scientific and reasonable, 
operability is high, mechanical operation is convenient, bio-
organic fertilizer is applied, soil loosening is convenient through 
insect luring, saline-alkaline resistant alfalfa planted in the first year returns to the field, the soil is improved, 
crop rotation is conducted in the second year and the third year, the content of soil salinization of a 
plough layer is reduced, and meanwhile great 
economic benefits can be generated from the crop.