The assimilation capacity and allocation pattern of carbon and nitrogen in plants not only determines the morphogenetic speed of different plant organs, but also closely related to the ecological strategy of the environment in which the plants grow. Carbon and nitrogen metabolism are highly interacted, and the allocation is highly interacted and mutually restraint, and in dynamic change, the allocation proportion is highly influenced by the sourcesink relationship of the plants. Changing light intensity results in the changes of morphological plasticity and physiological plasticity in plants. The utilization of light energy is also related to the carbon and nitrogen allocation in plants. Photosynthesis feedback regulation is resulted from changes in light intensity distribution through carbon and nitrogen allocation, mainly through influencing plant growth, photosynthesis and nitrogen assimilation. The explanation to the changes of carbon and nitrogen by the regulation of different light intensity at the molecular level,as well as the deep relationship between light intensity changes and the carbon and nitrogen allocation mechanism should be strengthened in the future research.