Construction method of ventilation hole and mold for making RC floor ventilation hole

This invention relates to a construction method of ventilation hole and a mold for making an RC floor ventilation hole, comprising: separately installing bases on a template; carrying out a steel bar tying operation to reduce the construction costs of tying steel bars; then sleeving a cylindrical mold at each base and installing a plurality of adjustment supports so as to fine-tune the lateral positions of the cylindrical molds and fastening and securing the positions thereof by using the adjustment supports to ensure that the cylindrical molds are immobilized during the concrete casting operation; and passing a plurality of adjustment bolts through a cover board with their ends abutting the template to allow the adjustment bolts to optionally adjust the height of the cover board during the casting process, such that each cylindrical mold can be evenly and smoothly embedded in the concrete.