A lock cylinder assembly has a base, multiple selecting disks and multiple disk sets. The base has an axis. The selecting disks are rotatably connected to the base along the axis of the base. The disk sets are operationally mounted along the axis of the base and are respectively connected to the selecting disks. Each disk set has multiple disks operationally mounted along the axis of the base. Accordingly, a lock cylinder assembly that can increase the difficulty of unlocking the lock cylinder assembly to improve the safety of using the lock cylinder assembly is provided.