Microscopic quasi-elastic laser light scattering technique and image processing and analysis technology were used to study thalassemia erythrocytes. The mean hydrodynamic radius and average diffusion coefficient of hemoglobin polymers in the intact red cells, the membrane motion frequency, cross area,regular form factor,longest axis,shortest axis and mean gray were measured for thalassemia erythrocytes and normal red cells. It is found that, compared with normal red cells, the mean hydrodynamic radius and its variance of thalassemia erythrocytes are larger, the membrane motion frequency is slower and the cross area of the cell is smaller. This suggests that thalassemia erythrocytes have large hemoglobin polymers and worse deformability.