The invention provides a single-string all-round drilling ahead and jet grouting drill bit which can open/close an auxiliary grouting hole by hydraulic control and comprises a drill bit body (1) with a hollow cavity (7) inside, a high pressure nozzle (5) is arranged on the wall of the drill bit body (1), the lower end of the drill bit body (1) is provided with a drill tip (2), a grout passage (8) which is communicated with the hollow cavity (7) is arranged at the lower part of the drill bit body (1) and in the drill tip (2) axially, an auxiliary grouting hole (6) which is communicated with the grout passage (8) is arranged on the wall of the drill tip (2), a hydraulic controlled cut-off valve (10) is arranged in the grout passage (8), which closes the grout passage (8) when the pressure of fluid in the hollow cavity (7) is at or above a set value. The single-string all-round drilling and jet grouting drill bit aims to provide a single all-round drilling ahead and jet grouting drill bit which can open/close an auxiliary grouting hole by hydraulic control and can lubricate and cool the drill bit during drilling ahead, is highly efficient in drilling ahead, can close the auxiliary grouting hole very conveniently by hydraulic control and can adjust the grouting volume as needed.