The effect of Cr element in ultra-high strength cord steel on the microstructure and properties of LX82A wire rod and drawn wire is studied by JMatPro software， metallographic microscope， scanning electron microscope and tensile properties test. The results show that：For the 82 grade cord steel，by reducing Mn content to 0.18% and increasing Cr content to 0.35%， the C curvel moves down to the right， and the strength of LX82A wire rod increases from 1 150 MPa to 1 175 MPa， and the strength of copper plated cord steel wire increases from 1 235 MPa to 1 290 MPa. The strength of finished wire is increased by 40 Mpa， and the strength of finished wire exceeds 3 650 MPa. Because the addition of Cr reduces the soxlet phase transformation temperature and refine the spacing of the lamellae ， it improves the steel wire drawing hardening ability. Through the design and application of Cr element， it improves the steel wire drawing hardening ability， improves the strength of ultra-high strength cord steel， to achieve the high strength and toughness requirements of drawing steel wire.