Korean technological innovation is characterized by large firm-leading and characterized sector such as electricity and electronics. We examine the relationship between two elements. Using patent data registered at USPTO by Korean firms, We examine the relationship between patterns of innovative activities and sectoral specialization. As a result, Korean technological innovation is characterized by relatively high asymmetry, big share of large firms, high stability of ranking of innovators and diminishing role of newcomer, therefore as close as Schumpeter Mark II. But technological specialization is associated positively with the big share of large firms, negatively with low stability of ranking of innovators. It means that Korean technological innovation is led by large firms, but quantitative growth and technological specialization is achieved through competition between them.