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. <EOS>