Abstract: As the scale of rock engineering projects continues to expand, the instability of composite layered rock masses and anchor bolt fracture caused by deformation damage in weak interlayers have become increasingly prominent issues. Meanwhile, water level fluctuations (rising and falling) or rainfall constitute the main external force exerting cyclic loading and unloading on rock mass anchorage systems. Therefore, by combining the two-dimensional (2D) discrete element method with indoor pullout tests, the anchor resistance, displacement field, and micro-fracture propagation characteristics within rock masses under different loading modes were investigated at the mesoscopic level. The results reveal that the cyclic loading effect is equivalent to a type of "time acceleration", significantly shortening the time required for the rock mass anchoring structure to reach its preset service life. The displacement field of the rock mass is symmetrically distributed in a "U" shape, and shear contraction occurs within the anchor. Convergent micro-fractures are distributed at the end of the anchor, and the extension range of these micro-fractures increases with the number of cycles. When the rock mass contains mudstone interlayers, the mudstone rock particles exhibit significant shear dilation under cyclic loading. With increasing thickness of the mudstone layer, the peak pullout resistance of the rock-anchorage system decreases significantly, and the distribution pattern of micro-fractures changes from a uniform distribution to an inverted "V" shape. Under the same mudstone layer thickness, the number of microfractures is greater under high-frequency cyclic loading than under low-frequency cyclic loading, with the majority located inside the mudstone rock. The results provide a reference for understanding the anchoring mechanism of composite layered rock masses containing weak interlayers and for optimizing the stability control design of rock engineering.