Abstract: On observing the microcirculation blood flow of 12 rats suffering from cremaster muscle hemorrhagic shock in vivo,the test for dynamic determination of edge cell-free plasma layer in arteriolar blood flow in vivo is conducted using the high magnifying microscope video image system and through microcirculatary digital imageprocessor(MCIP) techniques.The expansible mechanism of the cell-free plasma layer of rat in hemorrhagic shock is studied by tracking in accordance with hemorheology.The experiment studies indicate that the plasma layer thickness decreases while lowering RBCs velocity,and the blood flow doesn't slagnate when the plasma layer disappeared.The expermment shows the decreasing speed of the plasma layer thickness is greater than that of RBCs velocity,It indicates that one of the major factors that effects upon the microcirculatory disorder is the gradual disappearing performance of cell-free plasma layer.The thickness of the cell-free plasma layer in microvessels will be one of the important clinical parameters for reference in outcome treatment with patients recovered from shock;monitoring the expanse of cell-free plasma layer is of great help to turn the plasma layer to normal when the blood flow is disorded.