Novel asymmetric composite scaffolds of chitosan superfine powder (CSP) and biomedical polyurethane (BPU) were prepared by an immersion-precipitation phase inversion method. Effects of polyvinylpyrrolidone (PVP) as a pore-forming agent on the structure and performance of the CSP/BPU composite scaffolds were investigated. The morphology and structure of the composite scaffolds were verified via scanning electron microscopy, X-ray diffraction, and porosity measurement. The performance of composite scaffolds was characterized by determination of the swelling ratio, measurement of the water vapor transmission rate (WVTR), mechanical test, and degradation experiment. The result showed that all CSP/BPU scaffolds were asymmetric with a skin layer near the top surface and a porous supporting solid matrix. The porosity and average pore size of CSP/BPU scaffolds exhibited a maximum value at 5 wt% PVP. The crystallinity and the lamellar thickness (L) of composite scaffolds decreased with increasing PVP content from 0 to 8 wt%. The swelling ratio of CSP/BPU scaffolds also exhibited a maximum value as PVP increased to 5 wt%, which suggested that swelling ratios were controlled by the porosity, whereas, with increasing PVP content, the WVTR of CSP/BPU scaffolds increased and the tensile properties and degradation rates showed a decreasing tendency. Consequently, through adjusting PVP content, CSP/BPU scaffolds prepared by immersion precipitation phase transformation could be a potential material that could be applied in skin tissue engineering. (C) 2011 Wiley Periodicals, Inc. Adv Polym Techn 31: 310318, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20254