The invention relates to a 3D printing device based on internet-of-things, which includes: a cabinet body, a cabinet door, a printing mechanism, a self-locking mechanism, a workbench, and a central control mechanism. The self-locking mechanism includes a fixed shaft, a first gear, a second gear, a transmission rod, and a self-locking assembly. The self-locking assembly includes a third gear, a rotating disc, a connecting rod, and a self-locking rod. A work power supply module includes a work power supply circuit. The work power supply circuit includes an integrated circuit, a first capacitor, a second capacitor, a toggle switch, a first resistor, a second resistor, and an adjustable resistor. The model number of the integrated circuit is LM2931. The 3D printing device based on internet-of-things can achieve reliable sealing connection between the cabinet body and the cabinet door through the self-locking mechanism, so that printing reliability of the 3D printing device is improved. In addition, in the work power supply circuit, by means of sampling feedback to output voltage and then adjustment on resistance value of the adjustable resistor, stable adjustment on voltage of the work power supply is achieved, thereby improving the practicability of the apparatus.