Based on a phenomenological model for bubble break-up and coalescence, a new simulation model for gas hold-up and gas-liquid mass transfer in bubble column reactors is proposed. In order to describe bubble movements in a bubble column reactor, a compartment concept is combined with the phenomenological model for bubble break-up and coalescence. It is assumed that the bubble column reactor consist of a series of discrete compartments in which bubble break-up and coalescence occur and bubbles move from compartment to compartment with different velocities. Gas hold-up and gas-liquid mass transfer rate are evaluated on the basis of bubble behaviors, i.e., bubble break-up and coalescence. Reasonable agreement is found between the model predictions and the present experimental data obtained in two different size bubble column reactors with air-water system and available correlations in the literature. Simulation results indicate that the proposed model provides some insight into the transport phenomena in bubble column reactors and furthermore it is useful for improving CFD predicting gas hold-ups and gas-liquid mass transfer rates in bubble column reactors.