A cold-press forming process of a thick-wall bimetallic tee includes the following steps of step 1, the equipment arrangement is performed; step 2, straight pipe billets are placed in an inner cylinder and a mud-shaped pressure-bearing medium is injected into the straight pipe billets; step 3, a press machine is controlled to enable a pressure head of the press machine to drive a cylinder to move downward, the cylinder slowly enters the straight pipe billets to press the pressure-bearing medium, the straight pipe billets gradually protrude towards the inside of a circular hole, and the straight pipe billets are pressed to form the tee; step 4, the pressure head of the press machine moves upward, an outer cylinder is pulled upward through a rope to enable the outer cylinder to be separated from the inner cylinder, and two half cylinders can be opened to take out of the tee which is formed through pressing; step 5, a plugging end of a branch pipe portion of the tee is cut off along the radial direction to enable the branch pipe to be through inside and outside. The cold-press forming process of the thick-wall bimetallic tee is specially applicable to the forming operation of the thick-wall bimetallic tee and has the advantages of being simple in process, easy to operate, high in automation degree and good in forming quality and effect.