Provided is a vacuum-pumping connection test mechanism that comprises a box body. Three connecting pipes are disposed on different surfaces of the box body. Screws are sleeved on the three connecting pipes. The three connecting pipes are respectively used for being connected with an air exhausting pipe, a valve, and a precision vacuum meter. The valve is connected with a vacuum pump. The simple and practical vacuum-pumping connection test mechanism can be repeatedly used and effectively connected with a pre-embedded plate connection cover and a welding circular rod in order to guarantee an extremely strict test airtight requirement. The vacuum-pumping connection test mechanism can be popularized and used in vacuum-pumping tests of spent fuel pool pre-embedded plate connection covers and welding circular rods.