The low field NMR (LF-NMR) was used to analyze the distribution and migration of free water, semilow water, and bound water to reveal the migration mechanism of different forms of water, the interaction between different forms of water and their mutual transformation relationship during the drying process of carrot. It was found that the free water in carrot was mainly removed in the early stage, and the combined water was mainly removed in the later stage in the process of drying. It was showed that there were life characteristics of cells involved in the early stage of carrot drying because a small amount of free water was converted into bound water. As it was expected, the bound water was changed to free water in the later stage of drying. When the scanning electron microscope (SEM) images were analyze, it was found that the infrared dried materials had smaller specific surface area, larger void size, lower void tortuosity, umbrella delivery structure, greater permeability, and stronger seepage capacity than those dried by hot air. Through the analysis of transmission electron microscopy (TEM) images, it was found that the spatial structure of the cells of the materials dried by infrared was more regular and orderly than that of the materials dried by hot air，and the cell membrane, vacuole membrane and membrane structures on other organelles were all disappeared, and the area occupied by organelles became smaller than it was at the beginning. Since the “embedded” bound water in organic matter was separated from the complex structure of biomacromolecules after obtaining infrared radiation energy, these biomacromolecules were broken into many small molecules after losing the bonds. The mechanism of dehydration of carrot slices, the migration law of various forms of water in carrot, and the law of mutual transformation between various kinds of water under the action of infrared radiation were deeply analyzed. The research result not only provided theoretical basis and ideas for the design and optimization of drying process, but also provided technical support for the development and improvement of infrared drying equipment.