The non-pillar sublevel caving method is extensively employed in underground metal deposits due to its advantages of high mining efficiency, simple structure, and enhanced safety. In order to address the issues associated with the laborious design process and insufficiently intuitive simulation effect of medium-length hole blasting using traditional pillarless sublevel caving methods, this study conducted a simulation and application research on the medium deep hole blasting process based on the Aegis blasting design and analysis software. Firstly, this paper introduces the module composition and functions of the software while summarizing the simulation analysis process. Secondly, two key technologies were investigated: utilizing model boundaries to confine the blasting space and employing staggered states of blasting energy to verify borehole network parameters. Finally, numerical simulations were performed on medium-length hole blasting in a specific underground mine with non-pillar sublevel caving method using this software. The research findings suggest that the explosion energy in a single row of blast holes is concentrated and fills the entire explosion chamber. The design of continuously coupled charging structure and a powder factor of 0.3 kg/t is deemed reasonable in this context. It appears that there exists a tangential state for the blasting cavity walls between adjacent blast holes, indicating that the energy between rows may not be sufficient to completely break the rock mass. The distance between blast holes, which is approximately 2.2 m, seems slightly larger. Multiple routes were analyzed to predict the distribution of blasting fragmentation masses, all showing a high proportion of large blocks, consistent with field engineering practice results. For instance, based on photos taken after one blasting event, it was observed that large blocks accounted for 18.03% of the total pile volume. Simulation results from Aegis software analysis indicate that the large spacing between blast holes may be a primary factor contributing to this high block rate. Furthermore, through conducting 12 blasting tests on six mining routes within an experimental section and verifying these results through simulation analysis, consistent outcomes regarding proportions of block size and mass were obtained. This effectively supports the practical application efficiency of the software on-site. Overall, these findings contribute valuable insights into optimizing blasting techniques in rock excavation projects by considering factors such as explosion energy concentration and hole spacing to achieve desired fragmentation outcomes while minimizing undesirable block formation.