The invention relates to a method for intercropping sorgho and sesbania on a saline and alkaline land, and the method comprises the following steps of: A, soil desalting and land preparation: desalting the plowed layer soil of the saline and alkaline land, leveling the land, fertilizing, and seeding; B, intercropping, wherein the intercropping row number ratio of the sorgho and the sesbania is 1:3, namely one row of the sorgho is intercropped with three rows of the sesbania, the row spacing of the sesbania and the sorgho is 25-30 cm, the row spacing of the sesbania is 33-35 cm, and the row spacing of the sorgho is 100-105 cm; C, field management: thinning or filling seedlings when the sorgho has 2-3 leaves and the sesbania has 3-4 leaves, and singling one strain in every hole; and D, harvesting: harvesting the sorgho 7-10 days before grains are mature, reaping stalks and seeds, and reaping the sesbania before the grains are mature and cracked. The method disclosed by the invention promotes the balanced yield increase of the sorgho and the sesbania by utilizing the advantage complementary action of a symbiotic system of the sorgho and the sesbania, reduces the fertilizer addition, effectively remits the nutrient pinch obstruction of the saline and alkaline land, alleviates the secondary salinization of soil and enhances the composite utilization ratio of the land.