A 3D printing method of making a pharmaceutical dosage form, comprising: feeding a first initial pharmaceutical material to a first melt extrusion module of a 3D printing device through a first hopper of a first feeding module of the 3D printing device; feeding a second initial pharmaceutical material different from the first initial pharmaceutical material to the first melt extrusion module through a second hopper of a second feeding module of the 3D printing device; feeding the first initial pharmaceutical material and the second initial pharmaceutical material to a processing chamber of the first melt extrusion module; heating and extruding the first initial pharmaceutical material and the second initial pharmaceutical material in the processing chamber of the first melt extrusion module, so that the first initial pharmaceutical material and the second initial pharmaceutical material are melted into a first melt and the first melt is extruded from a discharge outlet of the processing chamber of the first melt extrusion module; measuring the composition ratio of the first melt at any position of the 3D printing device; controlling the discharge speed of the first initial pharmaceutical material at a discharge outlet of the first hopper of the first feeding module and the discharge speed of the second initial pharmaceutical material at a discharge outlet of the second hopper of the second feeding module according to the measured composition ratio of the first melt; and guiding the first melt at the discharge outlet of the processing chamber of the first melt extrusion module to be extruded through a first nozzle of a first printing module of the 3D printing device and deposited on a platform module of the 3D printing device. feeding a first initial pharmaceutical material to a first melt extrusion module of a 3D printing device through a first hopper of a first feeding module of the 3D printing device; feeding a second initial pharmaceutical material different from the first initial pharmaceutical material to the first melt extrusion module through a second hopper of a second feeding module of the 3D printing device; feeding the first initial pharmaceutical material and the second initial pharmaceutical material to a processing chamber of the first melt extrusion module; heating and extruding the first initial pharmaceutical material and the second initial pharmaceutical material in the processing chamber of the first melt extrusion module, so that the first initial pharmaceutical material and the second initial pharmaceutical material are melted into a first melt and the first melt is extruded from a discharge outlet of the processing chamber of the first melt extrusion module; measuring the composition ratio of the first melt at any position of the 3D printing device; controlling the discharge speed of the first initial pharmaceutical material at a discharge outlet of the first hopper of the first feeding module and the discharge speed of the second initial pharmaceutical material at a discharge outlet of the second hopper of the second feeding module according to the measured composition ratio of the first melt; and guiding the first melt at the discharge outlet of the processing chamber of the first melt extrusion module to be extruded through a first nozzle of a first printing module of the 3D printing device and deposited on a platform module of the 3D printing device.