In order to investigate the influence of He Ne laser irradiation on oxygen dissociation curve,blood is taken from the vein of a healthy man.The blood is washed by physiological salt water and then be made up into diluted blood.After being rediated by He Ne laser for about 20 min,the diluted blood is put into a closed bottle to decompression and deoxygenation.Next,a series different partial pressure of oxygen are arranged for the blood.The oxygen saturations of the blood are tested under every partial pressure of oxygen.The result indicates that laser irradiation can move the oxygen dissociation curve of red blood cell toward the left direction,at some conditions.This result implies that the laser irradiation can increase the oxygen carrying ability of the red blood cell.