Abstract: When myocardial ischemia and reperfusion in rabbits, the changes of hemorheologic parameters, such as red blood cell deformability, blood viscosity and plasma viscosity were stiuded in this paper. The results were as follows: red blood cell deformability were decreased more significantly in reperfusion group than in ischemia group, plasma viscosity and hematocrit were increased in reperfusion gloup. These results suggest that reperfusion can cause more injury to the red blood cell deformability and influence other hemorheologic parameters.