The invention discloses a square jacket fixing method of a drop switch, and belongs to the technical field of power transmission and distribution engineering. A drop switch fixing grip and a cross arm convex handle are just sleeved with a square jacket. Two cylindrical pins are penetrated into holes of two original bolts, and locked by split pins. Water is not accumulated in the cylindrical pins, and the cylindrical pins do not rust, and are convenient to replace; and two third of power-off time required by replacing can be shortened. The method is used for power transmission and distribution engineering overhaul.