In order to clarify the spontaneous imbibition oil displacement effect of surfactants in shale reservoirs and the influencing factors, spontaneous imbibition experiments under different factors were carried out using the shale oil reservoir core from the Huazhuang area of Jiangsu Oilfield, wettability, interfacial tension, and factors such as porosity, permeability, and microfractures were analyzed for their impact on the spontaneous imbibition effect and characteristics of crude oil utilization in shale pore throats using nuclear magnetic resonance T2 spectrum. The research results show: the stronger the surfactant improves the hydrophilic property of the core, the faster the imbibition rate, the better the oil displacement effect, and the higher the degree of crude oil utilization in the micro-pore throats. Appropriately reducing the interfacial tension of the surfactant is beneficial for improving the imbibition oil displacement effect. The larger the porosity, the higher the permeability, and the more microfractures, the better the imbibition oil displacement effect. In shale oil fracturing development, adding surfactants with significant improvement in formation wettability and appropriate interfacial tension to the fracturing fluid, the spontaneous imbibition oil displacement effect and EUR can be effectively improved.