Abstract: A molding system includes a bottom die having a bottom blind hole, an upper die controlled to mold a molding with the bottom die, and a water circulation system connected to the bottom die at a bottom side and having a T-hole disposed in communication with the blind hole on the bottom die for circulation of cooling water to cool down the bottom die and the molding molded in between the bottom die and the upper die, a leakage sealing device mounted between the water circulation system and the bottom die to seal the gap and to divide the T-hole into a water inlet and a water outlet, and a spiral water guide mounted on the bottom die and pressed against the leakage sealing device, the spiral water guide defining a spiral water circulation passage in the blind hole in bottom die for guiding cooling water from the water inlet to the water outlet through the blind hole in a spiral manner to evenly and quickly cool down the bottom die.