Abstract: Circadian genes are a group of genes in cells that can modulate circadian rhythm by self-expression and regulation of self-excited oscillations. These genes can maintain and regulate many physiological and biochemical activities of the human body to operate according to a certain periodic rule and order, so as to be better adapt to the surrounding environment. Period1 (Per1) gene is an important circadian rhythm gene and is at the core of circadian rhythm system. Studies have shown that the abnormal expression of Per1 and rhythm change are highly correlated with the occurrence and development of a variety of malignant tumors, but the mechanism is not fully clear. This article will review the effect of Per1 on the invasion, metastasis and apoptosis of malignant tumors and the related mechanism.