The invention relates to a novel 3D (3-dimentional) printer. The novel 3D printer comprises an excess material warning device, an external material receiving device, a multi-color printing spraying head device, a printing detection device, a 3D printer rack, a 3D printing material, a 3D printer material tray, a controller, an X-axis stepping motor, a Y-axis stepping motor, a Z-axis stepping motor, an X-axis synchronous belt, a Y-axis synchronous belt, a Z-axis transmission shaft and an alarm device; the excess material warning device can automatically remind workers of timely replacing materials; when printed materials are insufficient, standby materials are connected with existing materials by the external material receiving device, and therefore, the whole printing process can be finished continuously; different printing spraying heads are automatically exchanged to achieve the multi-color printing when the multi-color printing spraying head device works; the printing detection device is adopted to measure the rotating angles of the X-axis stepping motor, the Y-axis stepping motor and the Z-axis stepping motor, so as to detect whether a silk discharging route of each printing spraying head is deviated, and if the silk discharging route of each printing spraying head is deviated, an alarm is given, so that the defective rate of the printed models is reduced and the printing cost and the printing time are saved.