The corrosion kinetics and corrosion mechanism of Zn-Al alloy coated steel wire for 2100 MPa bridge cable in neutral salt spray environment were studied by means of electrochemical testing, corrosion loss measurement, scanning electron microscopy (SEM), X-ray diffractometer (XRD), ultra-depth of field microscopy (SDM) etc. The results show that the corrosion products of Zn-Al alloy coated steel wire are mainly composed of Zn(OH)₂ and Zn₅(OH)₈Cl₂·H₂O, and a small amount of Al(OH)₃ and Fe₃O₄. The corrosion behavior can be divided into four stages: the dissolution process of passivated film, the dissolution process of zinc-rich phase, the dissolution process related with the transition interval of zinc-rich phase and eutectic phase, and the dissolution process of Zn-Al eutectic phase. During the test period, the polarization resistance R_p of the Zn-Al alloy coating decreases first and then increase, indicating that its corrosion resistance becomes weak first and then becomes strong. In other word, the corrosion rate of the steel wire increases first and then decreases. There is no obvious corrosion pits formed on the steel wire matrix and no red corrosion products on the surface of the sample. The regression analysis of the corrosion-time curve shows that the corrosion rate increases slowly with the extension of the test time, indicating that the corrosion products have a delaying effect on corrosion, therefore, the Zn-Al alloy coated steel wire has a good corrosion resistance in the neutral salt spray environment.