Vacuum diffusion welding furnace is mainly used for diffusion welding of metal materials and ceramic materials. The heat shield of the vacuum diffusion welding furnace has an all-metal radiation shield structure composed of two layers of molybdenum and four layers of stainless steel. The heating element is a wide molybdenum belt, which is evenly arranged along the front, rear, left, and right walls to ensure uniform furnace temperature. The pressure device is composed of a hydraulic station, a cylinder, a pressure head, a load cell, a pressure controller and a pressure bracket, which can realize oil pressure maintaining and pressure setting control. The electric control system adopts PLC and programmable temperature controller to realize three control modes: automatic, semi-automatic and manual, and the operation is flexible.