A 3D printing pen, comprising a control part, a drive part, a feed part, and a heating part, the control part, the drive part, the feed part, and the heating part all being installed in an inner rubber component (1), respectively being secured in preset installation positions of the inner rubber component (1), the inner rubber component (1) being entirely placed in an outer shell (2), an open end of one end of the outer shell (2) being secured by means of a tail fastener (3), and the other open end being sealed by means of a pen nib outer shell (4), and the heating part being installed at an output end of the feed part; the control part comprises a control board (5), the control board (5) being respectively electrically connected to the heating part and the drive part (7) by means of an interface groove; the present 3D printing pen uses gearbox mechanical deceleration, a relief bearing structure, and dual-shaft synchronous delivery of raw materials, greatly improving the technical bottleneck of material blockages faced by current 3D printing pens, and thus significantly improving the experience of the user of the 3D printing pen; residual material in the channel can be easily removed by means of the removable feed part, facilitating maintenance.