In order to better evaluate the effect of vertical well fracturing in low-permeability reservoirs, an oil–water two-phase flow model and a well model were established. Based on this, a method for evaluating the effectiveness of vertical well fracturing was proposed. Divide the reservoir transformation area into different secondary fracture areas, namely the core area closer to the main fracture and the external transformation area, to form a new method for evaluating the effect of vertical well fracturing transformation in low-permeability oil reservoirs. Through model calculation and analysis, it is found that the changes in pressure during different periods are mainly caused by different influencing factors. The change in the half length of the crack is related to the early stage. The core area of the main crack mainly affects early production capacity, the external secondary crack area mainly affects medium and long-term production capacity, and the matrix permeability mainly affects the fluid flow law at the far end of the crack. The research method in this article provides a new approach for evaluating the fracturing effect of low-permeability reservoirs.