The light scattering characteristics and the body characteristics of red blood cells (RBC) are studied in the paper, and from it, a single ellip soidal model is setup and the scattering compose differences between the ellip soidal model and spheroid model are researched particularly. A non-linearity relation of the body influence of RBC is gotten in mathematics,meanwhile, a probability distribution function of the body of RBC is setup based on the body distribution stat-character of RBC. After that, a new perturbation modification theory about body influence of RBC is also brought forward based on the trouble-theory, and these offers a effective theory to advance measuring and analyzing technology of RBC.