With the expansion of human activities in Antarctica, understanding snow strength characteristics has become crucial for developing transportation infrastructure such as snow roads and runways. Previous studies have established that the uniaxial compressive strength of snow is primarily governed by density and sintering time, and that pressure sintering can significantly reduce the time required for snow layers to achieve target strength. However, the strengthening effects of pressure sintering on reconstituted and compacted Antarctic snow and the underlying mesoscale mechanisms remain poorly understood. This study addresses this knowledge gap through experiments on reconstituted and compacted Antarctic snow, comparing pressure sintering (experimental group with 40 KPa pressure) with conventional sintering (control group). Results demonstrated that the experimental group achieved a final density of 0.521 g cm −3 and 86% higher compressive strength of 0.246 MPa compared to the control group’s 0.500 g cm −3 and 0.132 MPa, respectively. Mesoscale analysis demonstrated that the minimum cut density index increased by 54% in the pressure-applied direction. Similarly, the directional connectivity index showed a 39% improvement along the same axis. Additionally, the process resulted in increased mean structure thickness (representing the average local dimension of the ice matrix) and microstructural orthotropy of the experimental group. The findings herein provide a theoretical basis for optimizing snow compaction techniques in Antarctic snow engineering.