Abstract: OBJECTIVE To determine apparent partition coefficients of chlorogenic acid and to investigate its absorption kinetics in the whole small intestine and different intestinal segments of rats. METHODS The shake-flask method was employed to determine the O/W partition coefficient of chlorogenic acid， and rat single-pass intestinal perfusion technique was employed to investigate the absorptive kinetics of chlorogenic acid. RESULTS The partition coefficient(P) of chlorogenic acid was 26.07（logP1.42）；There were a little significant difference (P<0.05) between the value of Peff of chlorogenic acid at three concentrations (10， 20 and 40  μg/mL)， and no significant difference between different intestinal segment. CONCLUSION There is little difference in apparent partition on coefficient in acidic and neutral phosphate buffer solution. Besides passive diffusion mechanism， other transports methods also worked， and chlorogenic acid could be absorbed in rats' every intestinal segment.