The invention relates to a hydraulic brake device of a module transport vehicle, comprising a wheel brake with an internal brake disc, a pedal, a hydraulic cylinder, wherein the hydraulic cylinder comprises a hydraulic oil inlet, a hydraulic oil outlet and a piston with a piston rod; the hydraulic oil inlet is provided with a one-way valve; the pedal is in transmission connection with the one-way valve; a link mechanism is arranged between the piston rod and the wheel brake disc; the piston rod and the brake disc are in transmission connection by the link mechanism; and when a driver steps down the pedal, the one-way valve is opened, the hydraulic oil enters the hydraulic cylinder by the hydraulic oil inlet, and the piston rod is moved under the pushing of the hydraulic oil and acts on the brake disc by the link mechanism so as to realize braking. The hydraulic brake device can generate larger power, that is to say, under the same power, the hydraulic device is small in volume, light in weight and compact in mechanism and has larger working pressure.