Guided tissue regeneration (GTR) membranes with bioresorbable characteristics have been employed in recent years for periodontal procedures to deflect the growth of gingival tissues away from root surface. They provide an isolated space over regions with defective tissues and allow the relatively slow-growing periodontal ligament fibroblasts to be repopulated over the root surface. In this study, we employed chitosan and CaSO4 composites as one of the viable membrane materials and evaluated their roles in GTR applications. Two types of CaSO4-chitosan composite membranes with molecular weights of chitosan 70 kDa and 300 kDa, respectively, were prepared for study in three categories: mechanical strength to create and sustain an effective space; rapid rate to reach hydrolytic equilibrium in phosphate buffer solution; and ease of clinical manipulations. Consequently, standardized, trans-osseous and critical-sized (cavity of 6 mm) skull defects were made in adult rats, and the defective regions were covered with the specifically prepared chitosan membranes. After 4 weeks of recovering, varying degrees of bone healing were observed beneath the CaSO4-chitosan composite membranes in comparison to the control group. The CaSO4-chitosan composite membrane-covered regions showed a clear boundary space between connective tissues and bony tissues. In summary, good cell-occlusion and beneficial osteogensis effects by these bioresorbable GTR materials toward the wound recovery were indicated.