The invention discloses a 3D printing device, comprising a main frame, a discharging printing head, a forming printing table, and a printing head displacement adjusting mechanism for driving the discharging printing head to move so as to change the position of the discharging printing head. The discharge print head is provided with a print head feed end for inputting printing raw materials, the discharge print head is provided with a discharge channel communicated with the feed end of the print head, and the forming printing table includes a fixed platen, at least A movable platen that can move up and down, and a platen displacement adjusting mechanism that corresponds to the movable platen one-to-one and is used to drive the movable platen to move up and down. The beneficial effects of the invention are that the structure is reasonable, can be adjusted according to the support requirements, and flexibly provides a part of the original support (non-printing support), thereby reducing the demand for the original printing support, improving the printing efficiency, reducing the risk of partial collapse of the product, Save support material and ensure product stability during printing.