Mesoporous polymer membranes are important in various separation processes and have become more crucial with increasing concerns in environment protection. Here, we report novel mesoporous membranes of polyvinyl chloride (PVC) nanofibers prepared via a modified freeze-extraction technique. The as-prepared nanofibers have an average diameter of similar to 45 nm and are dispersed heterogeneously in an ethanol solution. The nanofiber formation is studied in detail. The resulting nanofiber dispersion is directly filtered on a macroporous support to fabricate mesoporous membranes. The as-fabricated membranes have a controllable thickness ranging from 360 nm to 1055 nm, and a high porosity up to 63% that is at least 5 times greater than that of most of the commercial ultrafiltration membranes. These membranes present an ultrahigh water flux up to 6612 L m(-2) h(-1) bar(-1) and a good ferritin rejection during ultrafiltration. Moreover, these membranes show a fast and high-efficient absorption for Methylene Blue (MB). The newly developed mesoporous membranes have a great potential application in various separation processes.