Staged fracturing method adopting under-pressure dragging

The invention relates to the technical field of petroleum extraction, in particular to a staged fracturing method adopting under-pressure dragging. Wellhead equipment of the staged fracturing method comprises a wellhead flange plate, a wellhead four-way valve, a pulley and a steel wire and cable in-position tool, and is characterized in that the staged fracturing method adopts the manner that a plurality of construction layer stages are implemented one by one, and particularly seven steps, namely installation of wellhead equipment, fracturing construction on a first construction stage, setting of the first construction stage, pressure leakage of the first construction stage, annularly upwardly pulling an oil jacket to drag a pipe column, fishing a steel wire blanking plug and fracturing construction of follow-up construction stages. The staged fracturing method adopting under-pressure dragging can avoid open flow processes after the complete of each construction stage in a staged fracturing technology are avoided, so that 3-5 construction hours can be saved in each stage, and staged fracturing construction efficiency is greatly improved.