The design and experiments of an absorbed dose calorimeter in quasi-adiabatic mode of operation and its measuring system are described. The absoption disk and outer shell of the calorimeter are made of anisotropic pyrolytic graphite. The graphite itself is used as heating resistor of the electrical heating unit

for the purpose of check and simulation. The ratio of calculated value and experimental value for temperature rising is 1.008. The standard deviation is less than 0.6%. The total uncertainty of absorbed dose determination. with the graphite calorimeter approximetes to 2.7% （K=2） for the 0.5-3.0MeV electron beam in the dose range of 1-5×102kGy. The powder alanine/ESR dosimeter and plastic thin-film dosimeter can

be calibrated by the calorimeter. The passivation of temperature rising curve

heat equilibrium

measurement of calorimetric ratio and its error are also discussed in this paper.