The Fuyang oil formation in Block A of Oilfield Y is a low-porosity and extra-low permeability reservoir. With conventional water injection development, the formation has poor water absorption, and the oil–water wells have not established effective replacement, resulting in a low degree of reservoir utilization. In order to improve the development effect of the block and increase the degree of reservoir utilization, large-scale fracturing of horizontal wells was carried out in Block A for elastic development. In order to investigate the fracture parameters of horizontal wells suitable for this block, the following research is made. This paper mainly applies numerical simulation method to study the influence of four factors, namely, fracture interval, fracture length, fracture width and fracture permeability, on the cumulative oil production of horizontal wells, so as to obtain the optimal fracture parameter interval. Through the sensitivity analysis, it was obtained that the factors affecting the cumulative oil production were fracture width, fracture permeability, fracture spacing and fracture length in the order. Through the design of each parameter combination, the optimal horizontal well fracturing parameter combination was selected. According to the research results, a total of 8 horizontal wells were deployed in the study area, and the preferred fracturing parameters were applied to predict the development indexes, and the simulation predicted that in ten years, the degree of recovery was increased by 12.4 percentage points, which effectively improved the degree of utilization of the reservoir. This paper has certain guiding significance for the design of the subsequent horizontal well program in this block, as well as the horizontal well fracturing construction.