The invention discloses a device and a method for continuous VGF crystal growth through reverse injection synthesis, relating to a device for preparing a semiconductor crystal and growing a single crystal, in particular to a method and a device for continuously growing the crystal in situ by using a VGF method and reverse injection synthesis. The device includes a furnace body, a crucible, a heat preservation system, a heating system, a temperature control system and an gas pressure regulation system, wherein the crucible is arranged in the furnace body, has a synthesis unit at its upper part, and has a crystal growth unit and a seed crystal unit at its lower part, and the synthesis unit is communicated with the crystal growth unit through capillary pores. Red phosphorus and boron oxide are put into the growth unit, indium and boron oxide are put into the synthesis unit, solid seed crystals are put into the seed crystal unit, and temperature and pressure are controlled to accomplish material synthesis and in-situ crystal growth. According to the invention, the capillary pores are used, the temperature and the pressure are controlled, the phosphorus bubbles rise to the indium melt in the material synthesis stage, rendering a full fusion of the two substances, and after the phosphorus gasification, the indium-phosphorus melt drops into the growth unit to finish the in-situ growth of the crystal.