This paper mainly studied the durability of square-section columns wrapped with CFRP by experiments. Three kinds of columns, such as columns without CFRP, columns wrapped with CFRP entirely and columns wrapped with CFRP strips, were considered. The environmental factors included dry and wet cycles of saltwater, the coupled action of freeze and thaw cycles and dry and wet cycles. The results show that the load bearing capability and the ductility of the columns wrapped with CFRP are improved greatly. The external environments have an ignoring effect on the damage model, the ductility and the stiffness of axial compressed columns, but they have an extremely effect on the load bearing capability. The load bearing capability of the columns wrapped with CFRP strips decreased more than that of the columns wrapped with CFRP entirely. And no matter how environments，the bonding between column and CFRP has no damage in this experimental study with the bonding length of 100mm.