The invention relates to the field of tunnel construction, in particular to a construction method for treating a tunnel deformation segment and accelerating tunneling, which solves the problems that a traditional method easily causes geological disasters such as water inrush, mud burst, collapse and the like, is long in construction cycle, poor in safety and the like. A tunnel face of the deformation segment is firstly divided into a stable upper step, a stable middle step, a deformation upper step, a deformation middle step and an integral lower step, and then excavation is started. The construction method includes: excavating the stable upper step and the stable middle step one by one; constructing a deformation upper step retaining wall; constructing a deformation middle step retaining wall; constructing temporary inverts for the stable upper step and the stable middle step; and excavating the deformation segment simultaneously from two ends by means of respectively oppositely constructing from the two ends of the deformation segment and excavating the deformation upper step, the deformation upper step retaining wall, the deformation middle step, the deformation middle step retaining wall and the integral lower step. The construction method eliminates the geological disasters such as water inrush, mud burst, collapse and the like to a large extent, and is short in construction cycle, high in constructional safety and wide in applicable range.