The invention provides a network reconstruction method and device for improving power supply capacity of a power distribution network. The method includes the following steps: performing cone relaxation on a power distribution network reconstruction model, and obtaining a relaxation model of the power distribution network reconstruction model; and determining a power distribution network reconfiguration plan according to the relaxation model of the power distribution network reconstruction model. The technical scheme provided by the invention solves the problem that a direct current optimal power flow algorithm which is widely used in a traditional transmission network cannot be applied in research of the power distribution network, network reconstruction is faster, modeling is more accurate, the calculation efficiency is higher, and the efficiency of network reconstruction for improving the power supply capacity of the power distribution network can be effectively improved.