Wetting hysteresis is an important factor affecting the production of oil reservoirs, especially in the nanopores of shale, and it has an important practical significance to study the influence of wetting hysteresis on fluid flow in shale oil reservoirs. The threshold pressure model and flow resistance model after the movement of the droplet in two-phase fluid systems were established on the basis of the static wetting hysteresis equation and dynamic contact angle equation, respectively. Combining the proposed models and experimental data in the literature, the threshold pressure and flow resistance with the varying flow velocity were obtained for different hydrocarbons in pores with different sizes. The results show that the threshold pressure and flow resistance both increase with the decrease of the pore size, and they cannot be ignored in nanoscale pores of shale oil reservoirs. Moreover, the flow resistance caused by the dynamic wetting hysteresis is greater than the threshold pressure caused by the static wetting hysteresis, and the flow resistance increases with the increase of the flow velocity. This work provides mathematical models for accurately characterizing the threshold pressure and flow resistance of two-phase fluid systems in nanopores, which will pave a way for the accurate numerical simulation of shale oil reservoirs.