Abstract: A kinetic model for supercritical carbon dioxide extraction was developed by mass conservation calculation of the extraction fixed bed.To determine the model parameter k_La,BP neural network was used to fit the experimental extraction elution curve,which was then compared with the elution curve calculated by the kinetic model with suggested parameter values.The parameter value was eventually determined through trial and error in the fitting process.The results showed that BP neural network could successfully fit the experimental data of the Rhubarb anthraquinone extraction kinetics curves, with 1.5% of training error and 3.5% of prediction error.The kinetic model with determined parameter can be used to describe the extraction bed with higher accuracy. The simulated extraction elution curve through the model had about 10% AARD error compared with the anthraquinone extraction experimental data.This model has the advantage over the others not only for better precision it offers, but also for the fact that it only requires moderate experimental conditions.