Mudstone, a frequently utilized material for embankment filling, tends to soften and disintegrate upon exposure to water. To address this, mudstone was modified through heating at elevated temperatures ranging from 140°C to 340°C. The hydrophobic characteristics of the mudstone samples were assessed using contact angle and water drop penetration time tests conducted at various modification temperatures and durations. Concurrently, mechanical and physical property evaluations were performed on mudstone samples subjected to different modification temperatures. The findings reveal notable enhancements in both hydrophobicity and mechanical properties of mudstone subsequent to thermo-modification. Specifically, heating the mudstone at 280°C for 40 min resulted in optimal hydrophobicity. At this temperature, the modified mudstone exhibited a remarkable increase of 104.2 % in uniaxial compressive strength and 85.7 % in characteristic breakage strength compared to the original sample. Throughout this range of modification temperatures, the composition of individual mineral constituents showed little variation. This enhancement primarily stemmed from alterations in the microstructure of the mudstone. Notably, at the modification temperature of 280°C, the mudstone demonstrated the highest proportion of micropores and the lowest proportion of macropores.