An expansion valve for a vehicle air conditioning system, comprising: a body member where a first path (F1) and a second path (F2) that are separate from each other are formed; a movement member combined to be movable in a predetermined direction in the body member , one end of the movement member being exposed to the first path (F1) and receiving a pressure of the first path (F1) and another end opening/closing the second path (F2); and an elastic member provided to elastically support the movement member in a direction of the first path (F1), wherein as the movement member ascends or descends due to a difference between an internal pressure of the first path (F1) and an elastic force (S) of the elastic member , the second path (F2) is closed or opened, wherein an orifice unit (F3) is formed on the second path (F2), the body member comprises a cylinder unit communicated with the first path (F1), and the movement member comprises: a piston unit received in the cylinder unit , an opening unit formed with a diameter that is greater than an interior diameter of the orifice unit (F3) to open/close the orifice unit (F3), and a connection unit connecting the piston unit and the opening unit , characterized in that the expansion valve does not include a diaphragm so that the orifice unit (F3) may be opened and closed due to a difference from a resultant force of only a force (F) generated when a pressure of the fluid moving through the first path (F1) is applied to the upper surface of the piston unit and the elastic force (S) of the elastic member . a body member where a first path (F1) and a second path (F2) that are separate from each other are formed; a movement member combined to be movable in a predetermined direction in the body member , one end of the movement member being exposed to the first path (F1) and receiving a pressure of the first path (F1) and another end opening/closing the second path (F2); and an elastic member provided to elastically support the movement member in a direction of the first path (F1), wherein as the movement member ascends or descends due to a difference between an internal pressure of the first path (F1) and an elastic force (S) of the elastic member , the second path (F2) is closed or opened, wherein an orifice unit (F3) is formed on the second path (F2), the body member comprises a cylinder unit communicated with the first path (F1), and the movement member comprises: a piston unit received in the cylinder unit , an opening unit formed with a diameter that is greater than an interior diameter of the orifice unit (F3) to open/close the orifice unit (F3), and a connection unit connecting the piston unit and the opening unit , characterized in that the expansion valve does not include a diaphragm so that the orifice unit (F3) may be opened and closed due to a difference from a resultant force of only a force (F) generated when a pressure of the fluid moving through the first path (F1) is applied to the upper surface of the piston unit and the elastic force (S) of the elastic member . a piston unit received in the cylinder unit , an opening unit formed with a diameter that is greater than an interior diameter of the orifice unit (F3) to open/close the orifice unit (F3), and a connection unit connecting the piston unit and the opening unit , characterized in that the expansion valve does not include a diaphragm so that the orifice unit (F3) may be opened and closed due to a difference from a resultant force of only a force (F) generated when a pressure of the fluid moving through the first path (F1) is applied to the upper surface of the piston unit and the elastic force (S) of the elastic member . <EOS>