The invention relates to a cryoablation catheter and a cryoablation system. The cryoablation catheter comprises a catheter body (5) and a freezing unit (3) wherein the catheter body (5) comprises a cold-source fluid input lumen (51) and a cold-source fluid output lumen (52), both extending in an axial direction of the catheter body (5), and the freezing unit (3) is arranged at a distal portion of the catheter body (5), and comprises a first balloon (31) in fluid communication with the cold-source fluid input lumen (51) and the cold-source fluid output lumen (52), and a second balloon (32) arranged external to the first balloon (31) with the length of the first balloon (31) being less than the length of the second balloon (32). When the first balloon (31) and the second balloon (32) are dilated, a cavity (6) for avoiding energy transfer is formed between the first balloon (31) and the second balloon (32), to prevent the energy transfer in a space of the freezing unit (3) corresponding to the cavity (6). The cryoablation catheter can effectively restrict the freezing-energy release area so as to reduce the probability of complications, and has wide application.
