The invention discloses a novel automatic reagent bottle capping and uncapping mechanism. A synchronous belt is driven by a stepper motor for transmission, a gear and rack transmission mode is adopted to realize uncapping, and a swinging arm is driven by an electromagnet to realize capping. The capping and uncapping mechanism is simpler and more stable; meanwhile, the mechanism is integrated with a reagent disk, so that cooling effects of the reagent disk can be effectively maintained, and the inner space of the reagent disk can be fully utilized to reduce more complex mechanical mechanisms; the reagent disk is integrated with the capping and uncapping mechanism, so that a reagent disk module of a fully-automatic chemiluminiscence analysis instrument is simpler and compacter in structure, and meanwhile, the working efficiency is improved; moreover, the reagent disk is closed, so that the aims of energy saving and emission reduction can be fulfilled, and the reagent disk can be used more conveniently and reliably, and has high market popularization value.