The International Symposium on Multiscale Simulations of Thermophysics 2023 was held in Shenzhen on June 02-04, 2023. Prof Tianshou Zhao, Prof Xinwei Wang and Prof Bingyang Cao served as the chair of the symposium, which was executively hosted by Prof Liang Guo at Southern University of Science and Technology, Prof Yangsu Xie at Shenzhen University and Prof Yuan Dong at Hangzhou Dianzi University.