The contributions by H. S. Tsien to modern mechanics and engineering sciences, especially his work on a series of key problems in aerodynamics, solid mechanics and jet propulsion, are introduced. Through his work, many new branches of engineering sciences were established, such as engineering dybernetics, physical mechanics, jet propulsion science, etc. The embodied foresight and realistic spirit are highlighted. Today in China, it is of great practical significance to advocate and carry forward his noble spirit, and to strengthen the research and development in the field of engineering sciences.