The invention provides a three-dimensional printing device. The three-dimensional printing device includes a base, a gantry, a forming platform, a holding slot, an adjustable platform, a driving module and a control module. The gantry and the holding slot are arranged on the base, and the forming platform is movably assembled on the gantry. The adjustable platform is arranged between the gantry and the forming platform, or is arranged between the holding slot and the base. The driving module is used for connecting the forming platform with the gantry. The control module is electrically connected to the driving module to drive the forming platform to do reciprocated movement along the gantry, so that the forming platform is moved into or out of the holding slot. Before three-dimensional printing is carried out, the control module moves the forming platform into the holding slot and enables the forming platform to abut against the holding slot through the driving module, the adjustable platform is driven and deformed, and it is confirmed that the contact surfaces of the forming platform and the holding slot are consistent.