A model, which was based on the rational assumptions, i) particulate organic matter in anaerobic degradation process are firstly hydrolyzed to soluble organics by hydrolytic enzyme, and ii) the production of the hydrolytic enzyme in the acidogens is induced by shortage of the soluble organics, and iii) the production rate is proportional to the acidification rate, was proposed to describe the hydrolysis and acidogenesis of particulate organic matter. The proposed model was consisted of 6 unknown variables, and 12 model parameters. In order to estimate the parameters, the mass balance equations for 6 variables were derived for a semi batch acidogenic reactor. The sensitivity analysis for VFA and SCOD as the state variables was performed and the parameters were classified into three groups, i.e. more sensitive group, sensitive group and less sensitive group. In order of the group sensitivity, the model parameters were determined by a nonlinear regression using the experimental data from the acidogenic reactor treating food waste. The experimental data was well fitted to the state variables of the model, and the adequacy of the description of the hydrolysis and acidogenesis could be improved if the model made up for the kinetic expressions to represent the effects of factors such as pH, temperature and substrate and product inhibition. The results of simulation under various dilution rates showed that the model might be a useful tool for design and optimization of acidogenic reactor of particulate organics.