To reveal the macro-micromechanical properties and phase transition-like failure mechanisms of weakly cemented sandstone in the Tiaohu Mining Area, Xinjiang, and to address the challenge of controlling roadway surrounding rock in this special stratum, a systematic experimental study was conducted on the microstructure and mechanical properties of Jurassic weakly cemented sandstone from the Tiaohu No.1 Mine. Nuclear Magnetic Resonance (NMR) technology was used to characterize the micro-pore structure features of weakly cemented sandstone from both the superficial soil segment and the bedrock segment. Triaxial cyclic loading-unloading tests under different confining pressures were performed using an MTS816 rock mechanics testing system to analyze the deformation laws, strength evolution characteristics, and phase transition-like instability mechanisms of sandstones with varying degrees of cementation. Considering the complex geological conditions of the mining area, characterized by fault cutting and fold development, a support philosophy centered on "active control" was proposed. A zoned, graded, and differentiated active support system was established, and its effectiveness was verified through FLAC3D numerical simulation. The results indicate that: the proportion of transition pores and fractures in the bedrock segment sandstone is higher than in the superficial soil segment, leading to stronger water conductivity, while the superficial soil segment sandstone contains a higher content of weakly cemented components, resulting in more significant slaking characteristics upon contact with water; the uniaxial compressive strength of the typical weakly cemented sandstone in the mining area is 1.5 to 2 times lower than that of similar sandstones in central and eastern China, exhibiting significant post-peak brittle failure characteristics with an almost complete loss of strength, indicating typical phase transition-like instability behavior; the sensitivity of damage evolution in weakly cemented sandstone to confining pressure increases with higher cementation degree, and a lower cementation degree leads to more pronounced phase transition-like failure characteristics; the optimized high pre-stress active support system can effectively inhibit the development of the plastic zone in the surrounding rock and improve its stress state. The research findings can provide theoretical basis and engineering reference for the support design of roadways in weakly cemented strata in the Tiaohu Mining Area and similar mines in western China.