In this paper the in-situ regeneration of deactivated catalyst were studied by means of dissolving the coke or coke precursores with supercritical reaction fluids. In a gradientless recycle reactor the kinetic investigation were performed on a zeolite-14 under supercritical conditions with ethylbenzene disproportionation as test reaction and butane as inert component. By comparing the experimental results under supercritical conditions and at normal pressure, it was found that a large power of the coke extraction exists under supercritical conditions. The influences of experimental conditions (temperature, pressure and feed molar fraction) on the ethylbenzene disproportionation and the coke removal were discussed. Under optimal supercritical conditions a long time experiment over 24 h was performed in an integral reactor, it turns out that the above 50% conversion level of ethylbenzene can be kept during the whole experimental time.