Abstract: With the rapid growth of fast, massive parallel computing power and steady improvement in mesoscale numerical models, there have been a growing number of numerical modeling studies of mesoscale convective systems (MCSs) using kilometer and sub-kilometer grid resolutions. These simulations have provided tremendous high resolution, dynamically consistent meteorological information that could not be obtained from current observations, and they have greatly improved our understanding of the internal structures and evolution of MCSs. However, some significant challenges remain in the future development of high-resolution numerical modeling. This paper reviews the progress that has been made in modeling convective storms with progressively increasing spatial resolution to one kilometer and sub-kilometer, and then introduces convective-scale data assimilation techniques and the approaches to the implementation of some important physical processes into mesoscale numerical models, including the “gray zone” problem associated with moist convection, planetary boundary layer, and radiation processes. Some typical studies on high-resolution (kilometer or sub-kilometer scale) simulations of convective storms are also presented. The future development and challenges in high-resolution simulation are finally discussed.