Organic solar cells (OSCs) have received widespread attention due to light weight, low cost, semitransparency and ease of solution processing. By continuously improving materials design, active layer morphology, and device fabrication techniques, the power conversion efficiency (PCE) of OSCs have exceeded 20%. The morphology of the active layer, which includes the phase separation structure, the degree of crystallinity of molecules, and the domain sizes, plays a critically important role in the performance, which is significantly influenced by the crystallization dynamics of the donor and acceptor. Therefore, it is crucial to comprehensively understand how the dynamics impact the film structure and how to effectively employ the kinetic procedure to enhance the structure of the active layer in OSCs. In this review, the methods and principles of kinetics characterization were introduced. Afterwards, the latest advancements in the control of film-forming and the post annealing process are outlined, unveiling the underlying mechanism. In conclusion, the potential and future of OSCs were anticipated and projected. Researchers may gain a comprehensive comprehension of how the dynamic process affects the morphology through this review, potentially enhancing the performance of OSCs.