This paper studied the biophysics’ index of low power laser irradiation on human’s red blood cell (RBC) to find the primary factor that affects biophysics of RBC. The blood cells of the deformability health human deposited in 4 ℃ for 48 h are used as samples, and the effects of low power laser irradiation on these samples are investigated. These samples are divided into two groups. One group is irradiated for 30 min under the laser with the powers of 2 mW, 4 mW, and 8 mW. The RBCs in the other group are doped with PBS with the same concentration. After centrifugating, they are processed in the same way. The results show that the characteristics of the blood cell irradiated by laser are less than the whole blood. Our study indicates that the magnify effects of the human’s red cells’ membrane are important to the rheology characteristic of the blood.