This article provides an analyzing work on the key complementary relationship between local excellent engineering projects and solid development of Engineering Science, referring such relationship as the law of symbiosis and mutual promotion, via typical historical cases in Western countries and cases in early new China during 1950’s in aero-industry. The article emphasizes that all local excellent engineering projects need new version of engineering sciences learnt and created, and equally, any development of local engineering science needs real engineering challenge-based success and local excellent engineers to learn and to create the version, together with the ever grand new product. The paper then raises corresponding call and suggestion for education reform for excellent engineers. The important conceptual engineering science is therefore emphasized to be well placed upon its local excellent engineering practice needs, critically differing from natural science, particularly from so called application of such science.