It deseribes the shear elasticity of the rat's aorta and the shear modulus of therat's aorta was determined by the testin g device in d ifferent conditions. The relationship of the dif-ferent inner pressu re of vessel and the shear modulushas been determined.A nd the effect of(NA)on the shear modulus was also dealt with .Some cuvveqL wete obtained too.