The utility model provides a tappet assembly, a valve valve mechanism and an engine, which relates to the technical field of an engine and is used to solve the technical problem of large wear of the tappet assembly. The tappet assembly comprises a sleeve and a tappet with an opening at both ends; The sleeve is used to connect with the engine body, and the sleeve includes a helical guide part; The tappet comprises a connecting part, and the tappet is arranged in a sleeve, and the connecting part is sliding in the guide part, one end of the tappet is used to connect with the CAM, and the other end of the tappet is used to connect with the push rod; When the CAM exerts a force on the tappet, the connecting part moves along the guide part so that the tappet moves upward along the rotation of the guide part. This allows the tappet to rotate and fall while moving up and down in the direction perpendicular to the CAM. Lower the friction between the tappet and the CAM, and then decrease. The wear degree of tappet is reduced and the performance of valve valve mechanism is improved.