To investigate the accumulation characteristics and mechanism of melatonin in cherry leaves of different leaf ages, the melatonin content and the expression of synthetic genes in cherry leaves of different leaf ages were measured. The results showed that the highest melatonin content was found in young leaves of cherry. By analyzing the expression of genes for melatonin synthesis in leaves of different leaf ages, it was found that there was a good correlation between gene expression and melatonin content, and the trend was similar, both young leaves were higher than mature leaves and old leaves. By measuring the melatonin content in cherry leaves and the expression of genes for melatonin synthesis, this paper revealed the accumulation rule of melatonin in cherry leaves, and provided a reference for studying the characteristics of melatonin accumulation in plant leaves.