A device for mapping and ablating renal nerves distributed on a renal artery, comprising a guide catheter, a mapping-ablation catheter, a handle and a connector, wherein: said guide catheter comprises at least one lumen and a distal end with adjustable curvature, wherein a first traction wire within the guide catheter connects the tip of said guide catheter to a controlling component in the handle, so that the distal end of the guide catheter bends by manipulating the controlling component; said mapping-ablation catheter is housed in one of the lumens of the guide catheter and has a distal end that comprises one or more electrodes and one or more detecting devices; said distal end of the mapping-ablation catheter can be extended out of or retracted into the guide catheter and is rotatable along the central axis of the open end of the guide catheter, wherein the distal end of said mapping-ablation catheter assumes a curvature when extended out of the guide catheter, said curvature is maintained by using a second traction wire, one end of which is fixed to the distal end of the mapping-ablation catheter while the other end is fixed to a spring inside the handle, wherein when the distal end of the mapping-ablation catheter is retracted into the guide catheter, the distal end is confined and stretches the second traction wire while at the same time the spring is compressed, wherein when the distal end of the mapping-ablation catheter is extended out of the guide catheter, the distal end is no longer confined and the spring restores naturally and pulls the second traction wire to cause the bending of the distal end of the mapping-ablation catheter; said handle connects the guide catheter and mapping-ablation catheter and comprises one or more controlling components, said controlling components are for controlling the movement of the guide catheter and mapping-ablation catheter; and said connector is designed to supply energy to the one or more said guide catheter comprises at least one lumen and a distal end with adjustable curvature, wherein a first traction wire within the guide catheter connects the tip of said guide catheter to a controlling component in the handle, so that the distal end of the guide catheter bends by manipulating the controlling component; said mapping-ablation catheter is housed in one of the lumens of the guide catheter and has a distal end that comprises one or more electrodes and one or more detecting devices; said distal end of the mapping-ablation catheter can be extended out of or retracted into the guide catheter and is rotatable along the central axis of the open end of the guide catheter, wherein the distal end of said mapping-ablation catheter assumes a curvature when extended out of the guide catheter, said curvature is maintained by using a second traction wire, one end of which is fixed to the distal end of the mapping-ablation catheter while the other end is fixed to a spring inside the handle, wherein when the distal end of the mapping-ablation catheter is retracted into the guide catheter, the distal end is confined and stretches the second traction wire while at the same time the spring is compressed, wherein when the distal end of the mapping-ablation catheter is extended out of the guide catheter, the distal end is no longer confined and the spring restores naturally and pulls the second traction wire to cause the bending of the distal end of the mapping-ablation catheter; said handle connects the guide catheter and mapping-ablation catheter and comprises one or more controlling components, said controlling components are for controlling the movement of the guide catheter and mapping-ablation catheter; and said connector is designed to supply energy to the one or more