Abstract: In 2007, on the 50th anniversary of the establishment of The Chinese Society of Theoretical and Applied Mechanics, Mr. Hsue-Shen Tsien wrote a letter to the society, pointing out that “mechanics have two aspects of service objects”. Mr. Pei-Yuan Chou has also made related statements. This paper presents a systematic description of the viewpoints on the two service aspects of mechanics proposed by the two presidents of the China Association of Science and Technology, and puts forward some thoughts and comments.