A design system of a casting system, the design system comprising: a database configured to store knowledge-based design basic information; an entity input module configured to receive a shape-related entity of a casting, to be manufactured, of the casting system to be designed; an entity creation module configured to create an entity for each component of the casting system based on the received shape-related entity and knowledge-based design basic information pre-stored in the database; a 3D shape creation module configured to create a 3D graphic shape of the casting system designed using the created entity for each component of the casting system based on the received shape-related entity of the casting and the created entity for each component of the casting system; and a graphic user interface, GUI, module configured to edit a design of the casting system according to a received edit command on a graphic user interface, GUI, on which a 2D graphic shape corresponding to the created 3D graphic shape is displayed, to dynamically modify the 2D graphic shape to correspond to the editing, and to display the modified 2D graphic shape to be used for said manufacturing, wherein the shape-related entity of the casting includes a size and shape of a mold, a core, and chill, and wherein the entity for each component of the casting system includes a first part entity including a pouring path, a path-line, an ingate, a joint, and a branch and a second part entity including a riser and a vent, wherein the ingate is an inlet through which molten metal flows into the mold, wherein, for editing a position of the ingate on the GUI on which the 2D graphic shape corresponding to the created 3D graphic shape is displayed, the GUI module automatically adjusts, in the 3D graphic shape, a height of the ingate in a shape of a flow path to match the height of the mold corresponding to the position at which the ingate is moved and displays an adjustment result according to an edit command of clicking and dragging/dropping the ingate. a database configured to store knowledge-based design basic information; an entity input module configured to receive a shape-related entity of a casting, to be manufactured, of the casting system to be designed; an entity creation module configured to create an entity for each component of the casting system based on the received shape-related entity and knowledge-based design basic information pre-stored in the database; a 3D shape creation module configured to create a 3D graphic shape of the casting system designed using the created entity for each component of the casting system based on the received shape-related entity of the casting and the created entity for each component of the casting system; and a graphic user interface, GUI, module configured to edit a design of the casting system according to a received edit command on a graphic user interface, GUI, on which a 2D graphic shape corresponding to the created 3D graphic shape is displayed, to dynamically modify the 2D graphic shape to correspond to the editing, and to display the modified 2D graphic shape to be used for said manufacturing, wherein the shape-related entity of the casting includes a size and shape of a mold, a core, and chill, and wherein the entity for each component of the casting system includes a first part entity including a pouring path, a path-line, an ingate, a joint, and a branch and a second part entity including a riser and a vent, wherein the ingate is an inlet through which molten metal flows into the mold, wherein, for editing a position of the ingate on the GUI on which the 2D graphic shape corresponding to the created 3D graphic shape is displayed, the GUI module automatically adjusts, in the 3D graphic shape, a height of the ingate in a shape of a flow path to match the height of the mold corresponding to the position at which the ingate is moved and displays an adjustment result according to an edit command of clicking and dragging/dropping the ingate.