The invention discloses a hydraulic self-locking quick-mounting blowout prevention device and method, wherein the blowout prevention device comprises a blowout preventer assembly, a central tube and a blowout prevention tube; the central tube is connected with the lower end of the blowout preventer assembly, the blowout prevention tube is branched from the central tube, and an upper flange plate is connected with the lower end of the central tube and correspondingly cooperates a wellhead lower flange plate. The blowout prevention device further comprises a space rotation fine-adjustment control mechanism and a hydraulic self-locking mechanism, wherein the space rotation fine-adjustment control mechanism is connected with the upper end of the blowout preventer assembly; the hydraulic self-locking mechanism sleeves the outer side of the central tube and hooks upwards and locks the wellhead lower flange plate, so that bolt-free quick clamping connection between the upper flange plate and the wellhead lower flange plate is achieved. According to the hydraulic self-locking quick-mounting blowout prevention device and method, no person is required to stand on a wellhead to mount a blowout preventer, and a blowout prevention device for the wellhead is quickly mounted by utilizing a mechanical manner, so as to win time for preventing blowout of an oil/gas production well.