The ribbon iron oxide phenomenon of X70M pipeline steel on cooling bed, which produced by 4 200 mm heavy plate mill of Zhanjiang Iron and Steel Co., Ltd. not only affected the surface quality, but also caused the final cooling temperature fluctuation of the heavy plate. The effect of descaling in the width direction of the heavy plate was validated by the descaling test through indepth analysis from mechanical and technological aspects. Combined with the effect of ribbon iron oxide on the finishing cooling temperature uniformity of steel plate after Mulpic rapid cooling, the descaling process system of finishing rolling was improved. On the basis of ensuring the final rolling temperature of the steel plate, the scale removal could be improved through the rational layout and new addition of descaling passes. The nearer the descaling pass was to the final pass of final rolling, the more significant the descaling effect was. A feasible scheme for the installation and maintenance of the descaling nozzle was proposed. Field application showed that the descaling of X70M pipeline steel could be improved by means of the above strategy.