The invention discloses a root restriction cultivation method of polygonatum multiflorum L. under high-slope forests. The method comprises seven aspects of seedling reproduction, forest selection, soil preparation and placement of root control devices, seedling transplanting, under-forest management, prevention and control over diseases and insect pests, harvesting and primary processing; according to the method, forests such as mixed forests, bamboo forests and broad-leaved forests where slopes are greater than 25 degrees, and ridging and formation of rectangular pieces of land are not easilyconducted are mainly selected, seedlings or seed stems (bud heads face upward) are planted in the root control devices, and a base fertilizer prepared by adopting a special formula and a planting substrate special for traditional Chinese medicinal materials are applied for planting. By adopting the method of cultivation of the polygonatum multiflorum L. under the high-slope forests, the problemscan be solved that at present, the utilization efficiency of the forest type is low, the impurity removal workload is high, according to traditional under-forest ridging cultivation of the polygonatummultiflorum L., the water and fertilizer utilization efficiency is low, soil-borne diseases are severe, and the yield and quality of the polygonatum multiflorum L. can be influenced; effective components of the obtained medicinal materials are consistent in content, stable and reliable, and can meet the standards of the 'polygonatum multiflorum L.' item of the 2015-version 'Chinese pharmacopoeia', and the method has a good popularization prospect.