Before 1980's,the world shipbuilding industry is vested in a structure of two poles,west Europe being one pole and Japan the other. By 1980's,with development of shipbuilding industries in Korea and other countries,the dually-polarized situation of world shipbuilding was gradually broken and the multi-polarizing trend of development appeared. The world shipbuilding industry began to form with a quadrupole structure featuring Japan,Korea,west Europe,and China representing other countries/regions. Japan and Korea were the two powers in the quadruple. This quadrupole situation was basically maintained throughout 1980's to 1990's.