In order to study the high-tech industrial development in Yangtze River Delta from 1995 to 2012, propose high-tech industry development index. The results show that: in total, the high-tech industries develop well and now are in the fast growth stage, the current order of development level is Jiangsu, Zhejiang and Shanghai, but the expansion of scale is still the main and quality improvement is limited; the structure and stability of high-tech industry in Jiangsu is the best, and the level of each industry doesn’t differ much, the electronic and communication equipment manufacturing ranks the first in the Yangtze River Delta now; by comparison, the high-tech industries in Shanghai develop slowly, the industrial structure is the worst, the leading one is the electronic and communication equipment manufacturing but the others are poor; the industries in Zhejiang are all in a period of vigorous development, especially the medicine manufacturing industry ,followed by medical equipment and instrument manufacturing. So each area should formulate corresponding policies combined with its own characteristics to consolidate the advantage industry and develop the poor one.