In this book, the formation causes and the control principles of the surface crack defects of micro-alloyed steel slab, such as the transverse corner cracks, longitudinal depressions in the wide-face off-corners, and the hot charging cracks were discussed. On this basis, the key technologies for the slab surface defects control were proposed. The contents of the book included the control technology for the transverse corner crack of conventional and wide and thick slabs of micro-alloyed steel, the control technology for thin slab corner crack of micro-alloyed steel, the control technology for wide-face longitudinal off-corner depression of thick slab, as well as the control technology for hot charging crack of micro-alloyed steel slab. This book can be read for the technical developers and scientific researchers engaged in slab continuous casting production of steel, and can also be used as a reference for teachers and students in colleges and universities of related majors.