The invention relates to a transplanting machine for tree saplings. The transplanting machine comprises a rack, a ditching device, a planting device and a compaction device, wherein the ditching device is positioned at the front end of the rack; the compaction device is positioned at the rear end of the rack; a through groove for conveying the tree saplings is formed in the rack; the planting device is arranged in the through groove formed in the rack and positioned between the ditching device and the compaction device. Ditching is carried out through power driving of a tractor, saplings are dropped under assistance of people, and semi-automatic sapling transplantation is realized by sensor positioning and release, and the plant space is uniform; the soil is compacted through a soil cladding plate and compaction wheels, so that the functions of one-time ditching, sapling transplantation, backfill and compaction are realized.