Abstract: Objective: To observe the effect of hypervolemic hemodilution on circulatory function of elderly patients with coronary heart disease during operation. Methods: 80 patients （with average age of 72.8 years old and body weight of 67.5 kg） undergoing non-heart operation received hemodilution which was accomplished by infusion of Ringer’s solution and 6% hydroxyethyl starch at the rate of 20 ml·kg^-1·h^-1 respectivly during the first hour of the operation. Hct, CVP, MAP, HR, ECG ST-T, SpO₂ and urine output were all measured at endpoints of preinfusion, 10 min after postinfusion and postoperation. Results: The mean Hct was decreased to 0.31 from 0.42 of preinfusion after postinfusion. CVP was increased to 1.17 kPa from 0.33 kPa. MAP and HR lowered from 14.9 kPa and 97bpm to 11.3 kPa and 83bpm. Ischemic sign of ECGST-T was also improved after solution infusion. This mild hemodilution could keep circulation in ideal state all through the operation.There was no urine with-in the first 50 mins but urine output was 68ml following 50 min of infusion and 650ml at the end of the operation. 79 cases were cured and discharged from hospital. One case died of myocardial infarction. Conclusion: Infusion at the rate of 40 ml·kg^-1·h^-1during the first hour of the operation not ohly helps to stabilize circulation, to improve microcirculation and heart function but also diminishes complications.