This paper presents a Pedestrian Simulation-Assignment (PSA) model for a selected Mass Transit Railway (MTR) station in Hong Kong. This selected station is Causeway Bay MTR station which is in the centre of a high density area. This PSA model was developed to simulate passenger movements within the station during the evening peak hour period. A simulation software package, Service Model, was adopted to develop the PSA model. The data collected was used to estimate the passenger origin-destination flow matrices. The speed-density functions for various pedestrian facilities calibrated in a previous related study were incorporated into the developed PSA model. To examine the reliability of the results given by the developed PSA model, an independent data set was collected. A comparison between the observed data and estimated results was conducted and conclusions drawn. It is believed that the developed PSA model for Hong Kong MTR station can be used for improvement of the passenger circulation within the station and maximize the realization of the station capacity.