It is over one year since COVID-19 broke out. The whole world is still struggling against the virulent pandemic COVID-19. It is still difficult to take international travel. Many conferences are held virtually, for the sake of protecting all the participants and conference staff from get infected by the virus.It is uncertain when the COVID-19 will end, so it remains unclear for postponement time, while many scholars and researchers wanted to attend this long-waited conference and have academic exchanges with their peers. Therefore, in order to actively respond the call of the government, and meet author's request, 2021 International Conference on Mechanics and Civil, Hydraulic Engineering(CMCHE 2021), which was planned to be held in Kunming, China from June 4 to 6, 2021, was changed to be held on 5th June, 2021 online through Zoom software. This approach not only avoids people gathering, but also meets their communication needs.The meeting focused on the research fields of “Mechanics” “Architecture”, “Civil Engineering” and “Hydraulic Engineering”. The aim is to provide a common forum for researchers, scientists, engineers, and practitioners throughout the world to present their latest research findings, ideas, developments, and applications in the area of architecture and civil, hydraulic engineering, to explore the development path of ecological civilization construction, and to cope with new opportunities and challenges.The conference brings together about 30 well-known scholars in the field of mechanics and civil, hydraulic engineering at home and abroad. The reports were divided into keynote speeches, oral presentations, and poster presentations to share their latest research results and experiences in related research fields. In the first part, each keynote speakers were allocated 30 minutes to present their talks via Zoom. After the keynote talks, all participants joined in a WeChat communication group to discuss more about the talks and presentations.We were greatly honor to have invited five distinguished experts as our keynote speakers. Prof. Chunfeng Wan, from Southeast University, China, was the first one to perform a thought-provoking speech: Structural health monitoring based on area sensing technology using distributed long-gauge FBG strain sensors. And then we had Prof. Chenghua Wang, from Tianjin University, China. He is the member of Technical Committee of Deep Foundation, International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE). Dr. Julian Hunt, from International Institute for Applied Systems Analysis, Austria. He presented an insightful speech: Swimming pool thermal energy storage, an alternative for distributed cooling energy storage. Prof. Mijia Yang, from North Dakota State University, U.S. He made a wonderful speech: Pore solution and its impact on durability of geopolymer concrete. Our finale keynote speaker, Prof. Yan-Gang Zhao, from Kanagawa University, Japan. Their insightful speeches had triggered heated discussion in the second session of the conference. The WeChat discussion lasted for about 30 minutes. Every participant praised this conference for disseminating useful and insightful knowledge.We are glad to share with you that we received lots of submissions from the conference and we selected a bunch of high-quality papers and compiled them into the proceedings after rigorously reviewed them. These papers feature following topics but are not limited to: Mechanics, Civil Engineering, Hydraulic Engineering and other relevant directions. All the papers have been through rigorous review and process to meet the requirements of international publication standard.We would like to thank the organization staff, the members of the program committees and reviewers. They have worked very hard in reviewing papers and making valuable suggestions for the authors to improve their work. We also would like to express our gratitude to the external reviewers, for providing extra help in the review process, and the authors for contributing their research result to the conference.Lastly, we would like to warmly thank all the authors who, with their presentations and papers, generously contributed to the lively exchange of scientific information that is so vital to the endurance of scientific conferences of this kind.Committee of CMCHE 2021Committee member, Committee chair, The Organizing Committee, Technical Programme Committees and this titles are available in this pdf.