A hydraulic forming die comprises an upper die body and a lower die body. The lower die body is a mold die body. The upper die body is an empty die body. An exhaust hole is formed in the bottom of a lower die cavity. An upper die cavity is provided with an oil inlet hole and an oil outlet hole. A sealing ring is arranged between the upper die cavity and the lower die cavity. An upper main die body and a lower main die body are locked through a locking bolt. A method for manufacturing a complex panel component through the hydraulic forming die comprises the steps that firstly, simulated analysis is conducted; secondly, charging and die assembly pre-tightening are conducted; thirdly, press locking is conducted; fourthly, compressed liquid is injected, and pressurizing is gradually conducted; fifthly, pressure maintaining is conducted; sixthly, pressure releasing is conducted, and the compressed liquid is discharged; and seventhly, die sinking is conduced, and the component is taken out. The die is simple in structure, short in design period and low in manufacturing cost. The middle procedures for manufacturing the complex panel component through the method are few, manpower and material resources are saved, the product thinning rate is low, and the wall thickness is uniform; the material forming extremity is high, the forming quality is good, precision is high, the bearing capability is high, and residual stress is low; and the problems that the complex panel component is prone to cracking and deformation due to drawing, and wrinkling happens to the edge pressing position are solved, and the hydraulic forming die and the method are particularly suitable for complex drawing structural pieces formed at a time.