The invention discloses a partitioned phased grouting reinforcement method, a construction method and an application. According to the reinforcement method, holes are formed in a working surface, orifice pipes with corresponding depths are tripped into the holes according to the depths of the holes, and a first reinforcement area is grouted by a short orifice pipe; a second reinforcement area is grouted by a long orifice pipe, another step is taken and so on, the first reinforcement area to the n reinforcement area are respectively grouted, and n is larger than or equal to 2; the orifice pipes with different lengths are distributed at intervals in surrounding rocks reinforced by grouting, and phased grouting reinforcement for loose surrounding rocks is realized by the aid of rapid hardening slurry. During deep grouting, owing to the isolation function of the long orifice pipe for shallow surrounding rocks, the slurry can be directly conveyed to the deep surrounding rocks, and the reinforcement method solves the technical problems that slurry can directly enter shallow grouted and reinforced areas without the long orifice pipe in the past, the shallow grouted areas are repeatedly grouted, and accordingly, grouting reinforcement effects of the deep surrounding rocks are weakened.