For the problem of scab cracks on the surface of finished wire rod after the 160 mm×160 mm continuous casting billet was rolled to the Φ11 mm wire rod for SWRCH10A peritectic steel produced by Xingtai Iron & Steel Co., Ltd., the cracks were detected and analyzed by optical microscope and scanning electron microscope. The test results show that there is obvious decarburization on the both sides of scab microscopic crack, and there is iron oxide scale inside the crack. At the same time, obvious macroscopic surface cracks are found on the surface of cast billet after low magnification pickling, and the scab cracks on the finished wire rod are caused by the remaining surface crack defects of cast billet after rolling deformation. According to the actual production situation, a series of measures are conducted to improve the appearance quality of cast billet by adjusting the cooling water flow of continuous casting machine crystallizer, reducing the drawing speed of continuous casting, and controlling the carbon content and the concentration of nitrogen and aluminum for the finished product, and finally the problem of scab cracks on the surface of wire rod is effectively eliminated.