The invention relates to the technical field of light regulation and control, in particular to a molecular mechanism research method for anthocyanin accumulation in pakchoi based on UV-A coupling. According to the method, during an experiment, excellent pakchoi seeds are firstly obtained, cultivation experiment work is carried out, finally obtained experiment data are more accurate, the credibility of the experiment is improved, then the seeds are placed in sterile water to be soaked, the seeds can rapidly absorb water, the germination time of the seeds is shortened, meanwhile, sterile water is used for soaking the seeds, the influence of bacteria on the seeds can be reduced when the seeds absorb water, the survival rate of the seeds is increased, meanwhile, the temperature and humidity of a seedling chamber and a phytotron are manually adjusted, the temperature and humidity are manually adjusted to be suitable for the growth of the pakchoi, the growth speed of the pakchoi is increased, during growth, UV-A coupling and blue light with different light intensities are used for light regulation and control work, and the anthocyanin component rich in the pakchoi is increased along with the change of time.