The invention discloses an intelligent variable-speed cruising system including amplitude sensors. The intelligent variable-speed cruising system comprises a variable tail fin device, an intelligent tail fin portion of an intelligent variable tail fin control device including an amplitude sensor for detecting the deformation amplitude of a main tail fin or auxiliary tail fins and an intelligent balance-adjustable force exerting portion including a balancing and force exerting device and an intelligent balancing and force exerting control device including an amplitude sensor for detecting the amplitude of the joints of the bent knee-ankle-hip parts of a swimmer. The auxiliary tail fins of the variable tail fin device are connected with a variable tail fin control part of the intelligent and variable tail fin control device through at least one linkage element between the two parts. Elastic elements of the knee-ankle-hip parts of the balancing and force exerting device are connected with a balancing and force exerting control part of the intelligent balancing and force exerting control device through at least one linkage element between the two parts. The balancing and force exerting device is connected with the variable tail fin device along its shank rod body, and the intelligent tail fin portion and the intelligent balance-adjustable force exerting portion are connected to form an integral structure.