A photoelectric method is presented as a way of detecting hepatic reserving function based on the dye dilution and remove functions.For blood sampling by spectrophotometry,the measurement is invasive and intermittent.When injected intravenously,the indocyanine green(ICG) dye is rapidly and completely bound by plasma protein,removed by the liver,as well as excreted by the bile.During the period,arterial blood ICG concentration decays exponentially.Two wavelengths of the peak absorption at 805 nm and the negligible absorption at 940 nm for ICG are selected to continuously record the first circulation and the recirculation curves according to the previously measured blood hemoglobin concentration,and then ICG plasma disappearance rate(K value) and 15-min retention rate(R15 value) can be computed.Compared with the "gold standard" method of blood sampling,the maximum relative errors of the two parameters are 8.12% and 7.37%,respectively,which can meet the clinical requirement and improve the evaluation level of hepatic reserving function.