In plants，anthocyanins are a group of flavonoid compounds and play an important physiological role in fruit coloring and tolerance to stresses. Foods rich in anthocyanins also have good health effects on the human，such as anti-aging and preventing hardening of the arteries. The biosynthesis and accumulation of anthocyanins are not only affected by their own structural genes，regulatory genes and plant hormones，but also by external environmental factors（such as light，temperature，etc.）. Among them，light is one of the important factors affecting the synthesis and accumulation of anthocyanins in plants. Therefore，it is of great biological significance to analyze the regulatory mechanism of plants from receiving light signals to affecting anthocyanin synthesis. HY5（ELONGATED HYPOCOTYL5）encodes an alkaline leucine zipper（bZIP）transcription factor， plays an important role in regulating plant growth and development. It is the first transcription factor found to be involved in photomorphgenesis. It also plays a key regulatory role in the biosynthesis of anthocyanins. Here，we review the role of HY5 protein in the pathway of anthocyanin synthesis，responses to light signals and activation of downstream transcription factors and structural genes，and interaction with BBX protein in regulation of anthocyanin synthesis and accumulation. We expect to provide insights for future exploring the functional basis of HY5 in the metabolic pathways of flavonoids and responses to light signals.