In order to provide pertinent evidence of ion channel with immune response in the fish,whole cell patch-clamp technique was employed for potassium ion channel study in turbot(Scophthalmus maximus) . Lymphocytes were isolated by Percoll density gradient centrifugation from peripheral blood samples,and electrophysiological characters of the channel were analyzed. In the recorded cells,activated voltage of the channels was-42.5 ± 3.7 mV and the average peak current was 313.12 ± 28.2 pA. The channel was identified as voltage dependent,the current was outward and it could be inhibited by 10 mmol/dm 3 TEA or 5 mmol/dm 3 4-AP,a specific potassium channel inhibitor,identifying the existence of potassium channel in peripheral lymphocytes of the turbot. In order to provide pertinent evidence of ion channel with immune response in the fish, whole cell patch-clamp technique was employed for potassium ion channel study in turbot (Scophthalmus maximus). Lymphocytes were isolated by Percoll density gradient centrifugation from peripheral blood samples, and electrophysiological characters of the channel were analyzed. In the recorded cells, the activated voltage of the channels was-42.5 ± 3.7 mV and the average peak current was 313.12 ± 28.2 pA. The channel was identified as voltage dependent, the current was outward and it could be inhibited by 10 mmol / dm 3 TEA or 5 mmol / dm 3 4-AP, a specific potassium channel inhibitor, identified the existence of potassium channel in peripheral lymphocytes of the turbot.