A novel hot extrusion tee joint forming process comprises the following steps: Step one, rolling steel plates: a stamped steel plate is divided into three areas arranged in parallel according to the depth, namely an end part area, a middle part area and a tail part area; the wall thickness of the middle part area is greater than those of the end part area and the tail part area; smooth transition; Step two, molding and welding a steel tube, and manufacturing the steel tube: a thickening area is formed on the wall of the area where the middle part area is; Step three, trepanning, extruding and forming a tee joint workpiece: marking out a line and trepanning in the thickening area; Step four, shaping processing: heating to about 900 DEG C, heat preserving, and shaping. The novel hot extrusion tee joint forming process is optimized based on the conventional process, comparatively simpler, saves the steel tube flattening and bulging processes, greatly saves the product manufacturing time, and improves the working efficiency; when the flattening and bulging processes are saved, the manufacturing and molding time of a tee joint is greatly reduced, and the entire production cycle is substantially shortened.