P4HA2, one of the important genes encoding the α subunit of collagen prolyl 4-hydroxylase （C-P4H）, is overexpressed in a variety of tumors and promotes tumor progression, and its high expression correlates with the poor prognosis of patients. In different tumors, P4HA2 can promote the proliferation, migration and invasion of tumor cells, increase the proportion of cancer stem cell population, and promote tumor cells to escape from immune system. An in-depth understanding of the role of P4HA2 in tumor progression may provide new ideas and insights for targeting P4HA2 to prevent or reverse tumor progression.