Abstract: Hypo-peritectic steels are widely used in various industrial fields because of their high strength, high toughness, high processability, high weldability, and low material cost. However, surface defects are liable to occur during continuous casting, which includes depression, longitudinal cracks, deep oscillation marks, and severe level fluctuation with slag entrapment. The high-efficiency production of hypo-peritectic steels by continuous casting is still a great challenge due to the limited understanding of the mechanism of peritectic solidification. This work reviews the definition and classification of hypo-peritectic steels and introduces the formation tendency of common surface defects related to peritectic solidification. New achievements in the mechanism of peritectic reaction and transformation have been listed. Finally, countermeasures to avoiding surface defects of hypo-peritectic steels duiring continuous casting are summarized. Enlightening certain points in the continuous casting of hypo-peritectic steels and the development of new techniques to overcome the present problems will be a great aid to researchers.