Cellulose-graft-polycaprolactone/polycaprolactone (cell-g-PCL/PCL) was formed by grafting cotton linter pulp with caprolactone via ring-opening polymerization catalyzed by Ti(O-n-Bu)4. The cell-g-PCL/PCL and polycaprolactone (PCL) were used to prepare porous materials (PMs) using solvent exchange and freeze-drying procedures. The obtained PMs were characterized by their porosity, tensile strength, and thermal stability via thermal gravimetric analysis and scanning electron microscopy. The preparation conditions of the cell-g-PCL/PCL PM were optimized based on the characterization results. Compared with PCL PM, cell-g-PCL/PCL PM showed higher porosity and better thermal stability. The adsorptivity of cell-g-PCL/PCL PM for the organic pollutant chlorobenzene was greatly improved compared with that of PCL PM. The adsorption processes of both PMs fit well with the Lagergren pseudo-first-order and pseudo-second-order kinetic models. The results of isothermal adsorption simulation indicated that cell-g-PCL/PCL PM and PCL PM fit better with the Langmuir model and Freundlich model, respectively.