The invention proposes a tee pipe hydraulic molding device. The tee pipe hydraulic molding device comprises an upper half mold and a lower half mold, wherein the upper half mold and the lower half mold are matched to form a main pipe mold cavity corresponding to a tubular blank, the lower half mold is provided with a branch pipe mold cavity which is communicated with the main pipe mold cavity to form a pipe blank mold cavity, and the two ends of the main pipe mold cavity are respectively provided with a side cylinder connected to a push press and a push rod of the side cylinder. The tee pipe hydraulic molding device is characterized in that the two push rods are respectively in clearance fit with the main pipe mold cavity, lubricating gaps are formed between the two push rods and the main pipe mold cavity, a liquid injecting hole connected to a liquid injection pump and an inner cavity of the pipe blank is formed in at least one of the push rods, and the liquid injecting hole is provided with a lubricating through hole communicated with the lubricating gaps; sealing devices used for sealing the lubricating gaps are arranged at the two ends of the main pipe mold cavity. The tee pipe hydraulic molding device can reduce the friction force between the tubular blank and the pipe blank mold cavity in the machining process, and therefore plastic deformation of the tubular blank can be facilitated; meanwhile, the tee pipe hydraulic molding device has the advantage of being simple in structure.