Construction method of upside-down type construction joint

The invention relates to the field of building construction, in particular to a construction method of an inverted hanging type construction joint. Comprising the steps that earth excavation is carried out, earth on the lower portion of a wall is lowered to the position 35 d below a foundation plane to be constructed, and d is the diameter of the wall; river sand backfilling is conducted, specifically, the over-excavation part in the first step is backfilled with river sand, and the position, 120 mm away from the bottom face of the foundation to be poured, of the top face of the river sand is backfilled; the construction method comprises the following steps: mounting a water stop steel plate, mounting a PVC sleeve, pouring a cushion layer, mounting reinforcing steel bars, mounting a template, pouring concrete, removing the template from the concrete, chiseling a construction joint, excavating earth, removing the cushion layer, an extruded sheet and the PVC sleeve at the construction joint after the earth is e