The invention relates to the technical field of tall fescue grass cultivation, in particular to a technology for cultivating and greening tall fescue grass on inshore mud flat saline-alkali soil. The technology includes the following steps of firstly, leveling a land; secondly, laying a mesh-shaped water irrigation and drainage pipeline net; thirdly, laying a sand layer; fourthly, laying an organic fertilizer layer; fifthly, sowing seeds; sixthly, strengthening seedlings; seventhly, shearing tall fescue grass and applying fertilizer; eighthly, conducting maintenance. The technology has the advantages that by lowering the underground water level of the inshore mud flat saline-alkali soil through irrigation and drainage measures, dehydration and dealkalization are rapidly achieved for the soil, and an environment suitable for growth of tall fescue grass is obtained. The technology can be applied to field greening construction of golf ranges, golf courses, football fields and the like in high-concentration salt and alkali regions, and can be applied to lawn greening, beautifying and damp preventing embankments and reservoir grassed slopes in coastal cities in high-concentration salt and alkaline lands; meanwhile, the technology plays extremely important roles in improving the ecological environment, improving the salt and alkali soil on a large scale, enlarging grain field areas, and relieving land arguing contradictories between urban lands and basic farmlands.