An ultrasonic thrombus removing system includes a front sheath tube (1) and a rear sheath tube (5) that are independent and that are inserted into a blood vessel (2); a rear end outer portion of the front sheath tube (1) is mounted with a front blocking balloon (105), and a front end outer portion of the rear sheath tube (5) is mounted with a rear blocking balloon (504); a breaking cavity (4) being formed between the two blocking balloons; the front blocking balloon (105) and the rear blocking balloon (504) expand or contract in the blood vessel (2) by means of the squeezing or loosening of an external force so as to block or open front and rear sides of the thrombus (3); an inner portion of the rear sheath tube (5) is provided with a core tube (502) that co-axially penetrates therethrough, a front end of the core tube (502).