The invention discloses a transplanter for greenhouse vegetable seedlings. The transplanter comprises a mechanical arm (1), a mechanical hand (2) and an automatic feeding system; the automatic feeding system comprises a seedling conveying device (3), a steering device (4), an empty tray recovering device (5), a seedling receiving device (6) and a protective pedal (7), wherein the seedling conveying device (3) is connected with the empty tray recovering device (5) through the steering device (4), the mechanical arm (1) is arranged above the seedling conveying device (3), the mechanical hand (2) is installed on the mechanical arm (1), the seedling receiving device (6) is arranged below the seedling conveying device (3), and the protective pedal (7) is arranged above the seedling receiving device (6). The greenhouse vegetable seedlings can be automatically transplanted through the transplanter, the transplanter is used for automatically conveying and receiving the seedlings, collecting seedling trays and conveying planting floating plates in the transplanting process of the greenhouse vegetable seedlings, the transplanting operation is not limited by manual seedling feeding speed and intensity any more, and the production efficiency of greenhouse vegetables is substantially improved.