Abstract: In this paper,the relation between the level of the reactive oxygen species(ROS) and relevant free radicals in the blood plasma of the BALB/c mice infected with Plasmodium berghei ANKA strain and their erythrocytic deformability(ED),and the relation between the ED and the Hb indices of these mice were studied by chemiluminescence(CL),induced CL(ICL) and laser diffraction method.The results indicated that the ED decreased with the increase of the level of ROS and free radicals in blood plasma when the anemia is developing.The use of antioxidants may restrain the course and raise the Hb index.The authors deem that the excess TNF produced in the later stage of malaria may induce the release of excess ROS and free radicals from phagocytes,which may cause damage on the deformability of erythrocytes and a drop in ED,resulting in the anemia of malaria.