In recent years, the GNP (General Gross National Production) of the major countries in the world shows apparent relation with their consumption of steel and the steel is reconfirmed as the backbone of the engineering materials. This is due to the fact that the steel making industry has been reformed perfectly by the high technique — Advanced Process Control System and brought out new steels with superior property as “high tech” steels. Micro-alloyed steel is one of the major high tech steels with largest market demand. Micro-alloyed steels are produced by the Advanced Metallurgical Manufacturing Process with addition of strong carbide and nitride alloying elements, i. e. , Nb, Ti, and V to refine their grain size in re-heating and to harden and toughen their matrix after rolling. There were developed the micro-alloyed steel of HW60R for the manufacture of large dumping trucks in open-mining, the line pipe steels of X52 ～ X65 for the construction of high pressure pipeline, and the micro-alloyed weathersteel for transportation container manufacture with great economic successes in China. In view of the micro-alloyed steels being environment conscious materials and the further development of high tough line-pipe steels, high strength ship steels and high tough SUF steel plate, the micro-alloyed steels are prospective in China in the 21 century.