Understanding the wetting behaviors of droplets on grooved surfaces is indispensable in surface science and offers promising avenues for advancing industrial processes. The droplet spreading on grooved surfaces can be discretized into a series of individual events that the droplet across each groove with variations in capillary forces and a subsequent re-equilibrium. In this work, a simplified model of droplet spreading on surface with an individual groove on both the left and right sides was utilized in order to elucidate the fundamental mechanisms underlying contact line pinning due to the groove. We examined the effects of the groove position and the wettability of solid surfaces. The contact line is observed to be pinned when the grooves are strategically positioned. However, by reducing the distance between the grooves, the contact lines can cross them. In such instances, the spreading process can be classified into four modes: Free spreading, impeding spreading, pinning, and depinning. The pinning and depinning phenomenon are explained by the balance between the driving force and pinning force on the contact line. Based on simulation results, the maximum pinning force exerted on the contact line by a certain solid surface can be theoretically predicted. Besides, the wettability of the solid surface also contributes to the impeding effect. This work provides theoretical guidance for the study of wetting on grooved surfaces at the nanoscale, which is essential for developing a comprehensive understanding of the interactions between droplets and structured surfaces, with potential applications in optimizing industrial processes and advancing surface science.