The invention discloses a splitting machine unwinding double-floating-roller mechanism and a closed-loop control method thereof. The splitting machine unwinding double-floating-roller mechanism comprises a driving floating roller, a driven floating roller, a cylinder and a connecting rod. The driving floating roller is connected with a driving floating roller swing arm. The driving floating rollerswing arm swings round a first rotary shaft. The cylinder drives the driving floating roller swing arm to swing. The driven floating roller is connected with a driven floating roller swing arm. The driven floating roller swing arm swings round a second rotary shaft. The two ends of the connecting rod are hinged to the driving floating roller swing arm and the driven floating roller swing arm correspondingly. The cylinder is driven by a motor. The motor is connected with a controller. A linear potentiometer is fixedly installed on the cylinder. When tightness of materials changes, the cylinderstretches out or retracts, the linear potentiometer on the cylinder detects change of the position of the cylinder, a voltage change signal is fed back to the controller, the controller adjusts the rotation speed of the motor, and thus the cylinder returns to the balance position. The splitting machine unwinding double-floating-roller mechanism provided by the invention is good in responsiveness,high in tension control precision and good in static and dynamic balance.