Abstract: Photosynthesis is the largest energy and mass conversion process on the earth, providing the essential foundation for almost all life. It is also the most significant biological carbon fixation process in the world. As the first step of photosynthesis, light reaction has a crucial effect on plant growth. With the development of modern interdisciplinary integration in recent years, new molecular elements have been identified for some classical regulatory pathways, and several new regulatory mechanisms have emerged. In this paper, we briefly introduce the light reaction of photosynthesis, then discuss the regulation mechanisms of photosynthetic light harvesting and electron transfer process based on the latest research progress. Research on plant light reaction regulation not only deepens the understanding of photosynthesis but also inspires optimizing crop growth to meet the world’s challenge of food and energy shortages.