The knowledge chain of science-technology-engineering-industry is studied in this paper based on their essences and meanings. It is pointed out that the connection of technology and engineering with economy is much tighter than that of science with economy. It is stressed that science-fundamental research is the transformation of capital to knowledge, and that the technology innovation is the transformation of knowledge to benefit and profit through market by the support of capital. Engineers are the important creators of new productive force and active pioneer of new industrial field. Engineers will confront with technology innovation at different levels, in different areas and on different scales. Much more attention must be paid to the creative work of engineers, especially in rapid economic growth period. The cultivation of a large number of qualified personnel in technology engineering is the requirement for promoting economic development and social progress.