The utility model provides a deep alluvium well drilling pit shaft broken wall injected hole oral siphon scour protection goes out device, including the drill way pipe, a back-up ring, consolidate the steel sheet, 4 the short stock of root, the high pressure tee bend, the pressure-relief valve, the high pressure ball valve, manometer and thick liquid blender, the one end of drill way pipe stretches into the wall of a well, other end dew is outside the wall of a well, the dew of drill way pipe is equipped with the retaining ring and reinforces the steel sheet in the extramural one end of well, the retaining ring sets up in the wall of a well and consolidates between the steel sheet, the centre drill of consolidating the steel sheet is equipped with round hole no. 1, the one set round hole is on the pipe of drill way, 4 jiaos of each brills consolidating the steel sheet have round hole no. 2, 4 the short stock of root passes round hole no. 2 respectively and will consolidate the steel sheet and fix with the retaining ring and the wall of a well, drill way guan lu links to each other at port of extramural one end of well and high-pressure three-way, pressure-relief valve and high-pressure ball valve are connected respectively to high pressure three-way two ports in addition. The utility model discloses the device, simple structure can prevent effectively that the injected hole oral siphon from rushing out, controlling the emergence of dangerous situations such as gushing water, sandblast, ensures pit shaft and constructor safety.