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 <EOS>