The invention discloses an apparatus for testing watertightness of a shield tunnel elastic sealing gasket in conditions with different bench staggering quantities. The testing apparatus comprises a rigid rib-equipped plate and four rigid flats. The rigid rib-equipped plate is composed of a main plate and a pair of rib plates. The rib plates are respectively arranged on the two sides of the main plate waist part in a staggered way. The rib plate staggering quantity is the bench staggering quantity of the elastic sealing gasket. The bench staggering quantity ranges from 1 mm to 14 mm. The apparatus for testing watertightness of the shield tunnel elastic sealing gasket in conditions with different bench staggering quantities overcomes the limits in a conventional test method that penetration performance of only the elastic sealing gasket and steel template contacting face is investigated. The apparatus which can have tests and researches performed for the penetration performance of the elastic sealing gasket and concrete contacting face better simulates the boundary conditions of the sealing gasket in real projects and achieves more objective and reasonable evaluating indexes. Furthermore, the testing apparatus can be used in a way to match a currently widely used common concrete anti-permeability instrument. The processing cost is further lowered.