A radiofrequency ablation electrode needle includes at least one first segment and at least two second segments. The at least one first segment and the at least two second segments are exposed on a surface of the needle body. An impedance of the at least one first segment is smaller than an impedance of the at least two second segments and at least one of the at least one first segment is disposed between two immediately adjacent ones of the at least two second segments. Besides, the radiofrequency ablation electrode needle is a monopolar electrode needle.