The invention belongs to the technical field of technical water jet machining and particularly relates to a multifunctional water jet machining device. The multifunctional water jet machining device comprises a five-axis linked water cutting machine tool, wherein the water cutting machine tool is provided with a water jet tool bit for cutting a part to be machined. The multifunctional water jet machining device is characterized by also comprising a multifunctional machining platform fixing the part to be machined and making the part to be machined to rotate horizontally and overturn vertically. The multifunctional water jet machining device has the advantages that the five-axis linked water cutting machine tool and the multifunctional machining platform are creatively integrated to form the multifunctional water jet machining device, the five-axis linked water cutting machine tool achieve cutting machining of shaft-shaped parts to be machined, the multifunctional machining platform fixes the parts to be machined and makes the parts to be machined to rotate horizontally, overturn vertically and perform linear reciprocating motion along a horizontal plane, the five-axis linked watercutting machine tool and the multifunctional machining platform cooperate to achieve turning of outer circles of the shaft-shaped parts to be machined, turning machining of flange step end faces and milling, cutting and polishing machining of rectangular grooves.