A highly reliable and detailed analytical model for the hollow fiber reverse osmosis module is reported. The model introduced concentration polarization into the transfer equations, which are usually neglected, combined with the pressure drop in the fiber bore. In this model, friction-concentration-polarization model (FCP model), the membrane transport equations were derived from the solution-diffusion model and the concentration polarization model while the pressure drop in the fiber bore was introduced with the Hagen-Poiseuille equation. The membrane permeability constants in the solution-diffusion model were experimentally determined. The mass transfer coefficients in the concentration polarization model were calculated by previously derived equations. The model was verified by reverse osmosis using Toyobo’s hollow fiber modules for both brackish water and seawater desalination, and showed good agreement.