Basement outer wall reserved hole pouring construction method

The invention discloses a pouring construction method for a reserved hole in a basement outer wall. The pouring construction method comprises the steps that a supporting beam embedded into the reserved hole in the basement outer wall is dismantled; construction joints around the reserved hole are treated; the reserved hole is subjected to waterproof treatment, grouting pipes are arranged around the reserved hole, and pipe openings of the grouting pipes are exposed out of the outer wall of the basement; reinforcing steel bars are constructed in the reserved holes; a formwork is constructed at the reserved hole, and a horn mouth communicated with the reserved hole is formed in the upper end of the formwork on the side, away from the supporting beam, of the reserved hole; concrete pouring is conducted on the reserved hole through the horn mouth, and after concrete poured in the reserved hole is cured for a first preset number of days, the formwork is dismantled; performing waterproof construction on the basement