The invention relates to an automatic yam harvesting and planting machine, relating to an agricultural machine. Holes are dug for planting yams between two previous crop yams in order to avoid trench collapse. The harvesting and planting machine comprises a crawler chassis frame, a line-spacing sliding plate, a plant spacing sliding plate and a control and power system and further comprises frames arranged on the plant spacing sliding plate, yam receiving sleeve pipes and soil-loosening and hold-digging holes arranged in the frames. Line-spacing adjusting oil cylinders are arranged between the crawler chassis frame and the line-spacing sliding plate. A plant-spacing decreasing oil cylinder is arranged between two adjacent groups of plant-spacing lower sliding sleeves. The yam receiving sleeve pipes are connected with a material-taking elevating sliding seat. A plant-spacing increasing oil cylinder is arranged between two adjacent groups of plant-spacing upper sliding sleeves.Two ends of the material-taking elevating sliding seat are connected with the frames via guide wheels. The upper end of the material-taking elevating sliding seat is provided with a connecting plate and a material-taking elevating oil cylinder. Ridge separating operation is performed back and forth when yams are planted. Angles can be adjusted by ridging plates. The yam receiving sleeve pipes are used for sleeving roots and stems along with soil around without damage to yams. Soil is conveyed back to holes via material-receiving soil-returning plates.