It is difficult to ensure the design service life of the concrete square pile of suspended jetty constructed in the early years by conventional repair and reinforcement methods. For the problem，based on the distribution of chloride ion content in the pile，the pile concrete cover and the calculation results of the remaining service life of the pile，this paper studies the durability evaluation of the pile foundation of the old jetty. By cutting and casting of the pile head of the square pile of the old jetty，and innovative application of the installation of sacrificial anode to prevent the continuous corrosion of square pile reinforcement，the durability requirements are ensured. The construction of this project proves that this method is feasible，which not only avoids demolishing of all the old structure and cost saving，but also successfully applies the sacrificial anode technology to the anti-corrosion of concrete square piles.