Abstract: As the first heavy industrial base of China, the development of northeast China has went through fast growth under the old planned economy system and the regional revitalization since the implementation of openup policy. The upgrade and optimization of industrial structure, one of the core missions facing the revitalization of northeast old industrial base, have received many attentions from both researchers and policy makers. Many studies focused on the unique process and mechanisms of the industrialization of northeast China argued that great progress have been made in the upgrade and optimization of industrial structure since 1990s, but without further elaboration in details. So the paper focuses on the main characteristics and driving factors of industry structure evolution in northeast China since 1990, and attempts to provide some suggestions on the future upgrade and optimization of industrial structure in northeast China. The quantitative analysis of industry structure evolution since 1990 indicates that significant progresses have been achieved under the support of central government, foreign investment, market demand and the influence of regional environmental pressure, which can be manifest in following aspects. Firstly, the share of manufacture industry in total industrial output value increased while the proportion of mining industry declined significantly, the processing degree of industrial development had been strengthened. Secondly, the ascending share of heavy industry in total industrial output value had been curbed, promoted by the development of food processing industry, medical industry, communication and electronic equipment manufacture industry, the proportion of light industry increased slightly. Thirdly, the reformation of industrial ownership structure achieved remarkable success, more and more nonpublic ownership enterprises, such as stock enterprises, private and joint ownership enterprises, foreign and Hong Kong, Macao, Taiwan investment enterprises, emerged during the research period, the single industrial ownership structure had been gradually replaced by mixedownership structure. Finally, the reality of industrial development mainly determined by largeenterprises had been altered recent years, the average annual output value of small and mediumsized enterprises raised dramatically. However, there are still many problems need to be considered in the future upgrade and optimization of industrial structure in northeast China. Firstly, there had been little changes in the composition of dominant industries since 1990, regional industrial development still highly depends on heavy industries. Secondly, the growth of hightech industries is relatively slow, indigenous technique innovation ability needs to be improved. Thirdly, the optimization of industrial structure is mainly drove by exogenous factors，endogenous driving forces are relatively weak, and regional market environment is still far from perfection. Finally, the confliction between optimizing industry structure and promoting employment is emerging. Based on the problems mentioned above, future upgrade and optimization of industrial structure in northeast China should pay more attention on the relations between heavy industry and light industry, traditional dominant industry and newly emerging industry, capital  technique intense industry and labor intense industry, large enterprise and small & mediumsized enterprises.

Key words: northeast China, old industrial base, industry structure, evolution characteristics, driving factors