The invention relates to the field of agriculture, and discloses a water retention and soil fixation method for a peach orchard in a mountain area. The method comprises the steps that 1, ditching andridging are conducted according to the fruit tree line spacing being 2.0-3.5 m; 2, in early October, drilling planting is conducted in the radish, vicia villosa and paspalum natatum mixing sowing mode, wherein the sowing rate of radishes is 10-20 kg / ha, the sowing rate of vicia villosa is 30-60 kg / ha, and the sowing rate of paspalum natatum is 10-20 kg / ha; 3, after sowing is completed, the surfaceof soil is covered with rice straw, wherein the dosage is 2,000-3,500 kg / ha; 4, from early April to mid-June in the next year, the radishes, vicia villosa and paspalum natatum are harvested and all covered and subjected to earth backing. Accordingly, the method is suitable for a new-cultivating orchard in the mountain area in South China, the water and soil loss of the soil can be effectively reduced, the water retention and fertilizer conservation capacity of the soil is increased, physical and chemical properties of the soil are improved conveniently, and rapid growth of fruit trees is promoted.