An annular mapping catheter includes a catheter body. The catheter body has a distal end and a proximal end. The distal end of the catheter body is provided with a distal end assembly, and the proximal end of the catheter body is provided with a handle. The distal end assembly is made of a head end catheter that has a shape memory function. The distal end assembly in a free state presents a predetermined bent shape including an annular part and a vertical part. The vertical part connects the annular part to the catheter body. The distal end assembly is provided with an electrode. The annular mapping catheter can detect an electrocardiogram activity near a pulmonary vein ostium and can better locate a cryoballoon in the heart.