Abstract: Coal pillars are the key structures that bear stress in mining districts. Under multi-stage mining disturbances, their stress state evolves continuously, and their instability and failure characteristics are closely related to the occurrence of rock bursts. Taking the full-cycle stress evolution of a panel coal pillar as the research object, the coal pillar was equivalently represented by standard specimens of a coal monolith (C), a coal-rock binary composite (RC), and a rock-coal-rock ternary composite (RCR). Conventional uniaxial compression tests and graded cyclic loading-unloading tests with variable upper limits were carried out. Combined with PFC2D numerical simulation, a comparative study was conducted on the deformation and failure characteristics, simulated acoustic emission responses, energy evolution, and fragmentation fractal laws of coal and composite specimens under different loading paths. The results show that all three types of specimens under both loading paths experienced the stages of compaction, elastic deformation, plastic deformation, and instability failure. Under cyclic loading-unloading conditions, the tangent modulus gradually decreased and converged, which can be used as a precursor indicator for instability. Cyclic disturbance promoted damage accumulation, causing the failure mode of the specimens to transform from abrupt failure under conventional uniaxial loading to progressive failure. Under conventional uniaxial loading, the fragmentation fractal dimensions of the C, RC, and RCR specimens were 2.421, 2.259, and 2.142, respectively; under graded cyclic loading–unloading with variable upper limits, the corresponding values were 2.213, 2.026, and 1.896, indicating that the overall fragmentation degree of the specimens was reduced under cyclic disturbance. Simulated acoustic emission results show that the ringing counts of the C specimens were mainly concentrated in the post-peak stage, accounting for about 62.5%, whereas the pre-peak ringing counts of the RC and RCR specimens accounted for about 60.0%, indicating that the weak coal part in the composites was damaged first and then triggered the overall instability. Energy analysis shows that, under conventional uniaxial loading, the elastic strain energy ratio of the three types of specimens was about 16%～25%, whereas under graded cyclic loading-unloading with variable upper limits, the elastic strain energy ratio decreased to about 10%, the dissipated plastic energy ratio remained stable at about 84%, and the kinetic energy release was relatively constrained. The results can provide a basis for stability identification of panel coal pillars under multi-stage disturbances and for monitoring and early warning of rock bursts.