The invention relates to a multifunctional wet brake for a forkman driving bridge. The inner side of a left shell of the brake is provided with an isolating ring, and a driving brake piston is positioned at the inner side of the isolating ring and is fixedly connected with the left shell by a bolt of a return spring; a parking brake piston is sheathed at the outer side of the isolating ring, compression springs of the parking brake piston are evenly distributed inside a right shell, and the outer end surface along the axial direction of the compression springs is contacted with a parking diaphragm plate; the inner side of the right shell is provided with more than two grooves along the radial direction, and the parking diaphragm plate and the circumference of the diaphragm plate are respectively and correspondingly provided with more than two convex blocks which are correspondingly positioned inside the two grooves of the right shell; the outer side of the left shell that is corresponding to the driving brake piston and the parking brake piston are respectively provided with an air bleed screw and a brake steel tube interface along the axial direction. The invention has compact structure and easy assembly; a brake steel tube and the air bleed screw are arranged on the side of the brake, so as to not interfere a charging connector; the operation is labor-saving; and the return spring has good return effect and short response time.