The invention relates to a hydraulic panel bulging device with a multipoint female groove. The hydraulic panel bulging device with the multipoint female groove comprises an upper mold and a lower mold, wherein the upper mold is provided with a liquid chamber corresponding to a cavity; a big through hole is formed in the middle of the lower mold; a back pressure mold connected with an ejecting cylinder is slidably arranged in the big through hole in a sealing way; positioning holes for installing small punches are formed in the upper surface of the back pressure mold; the small punches are uniformly distributed and tightly arranged; and the groove with the same shape as the bottom surface of a panel parts required to be manufactured is formed in the upper surfaces of the punches with same or different heights. A method for manufacturing a deep-cavity panel parts through using the hydraulic panel bulging device comprises the steps of S1, installing a panel blank; S2, installing the multipoint female groove; S3, exhausting and charging; S4, enabling the back pressure mold to close to the bottom surface of the panel blank; S5, carrying out initial contact molding; S6, drawing the mold for forming; S7, maintaining pressure; and S8, discharging oil and opening the mold. The bulging device can be applicable for producing panel pieces in different shapes without the need for replacing the mold, so that the cost is saved, the method is simple to operate and easy to control, the materials are saved, the efficiency is high, the occurrence of the phenomenon that the materials are cracked can be effectively avoided, and the bulging depth and the forming quality of the product are improved.