Surface pattern is a promising approach to enhance membrane performance while contradictory results have been reported on concentration polarization of patterned membranes. Here, we provide an experimental and modeling study of the concentration polarization on patterned membranes by varying pattern size, solute size, surface hydrophilicity and membrane orientation. Interesting trends were observed when comparing different membrane orientation, where relative concentration polarization degree (CPD) was found to be dependent on molecular weight. Salts and small organic molecules encountered more severe CPD in the transverse mode, while molecules larger than a threshold value showed a different trend. Such threshold molecular weight increased at larger pattern size. Simulation results were consistent with experimental observations, and revealed the critical role of diffusivity on such phenomena. Results also showed more severe concentration polarization on patterned membranes in both parallel and transverse modes in most cases, compared to smooth membrane.