Polyvinyl alcohol(PVA) bead crosslinked with boric acid has been widely utilized as a microorganism immobilization carrier. However, it has some disadvantages such as drastic cell viability loss, small adsorption capacity and mass transfer limitation. To improve upon these drawbacks, a new method to prepare PVA composite pieces with the addition of activated carbon (AC) and poly-3-hydroxybutyrate(PHB) was explored through a combination of freezing/thawing and the boric acid method and by using Tween-80 to improve the mass transfer performance of hydrophobic organics. m-Cresol and pyrene were used as representative compounds with benzene ring structures to model hydrophilic and hydrophobic organics in order to test the performance of PVA pieces. The results showed that, compared with the boric acid method alone, a combination of freezing/thawing and the boric acid method led to a decrease in total organic carbon(TOC) loss from 0.315 g g−1 to 0.033 g g−1 and increased the oxygen uptake rate(OUR) of microorganisms from 0.03 mg L−1·min−1 to 0.22 mg L−1 min−1. The m-cresol equilibrium adsorption amount of the PVA-SA(sodium alginate)-PHB-AC piece was 2.80 times that of the PVA-SA piece. The diffusion coefficient of pyrene in the PVA-SA-PHB-AC piece increased from 0.53×10−9 m2 min−1 to 2.30×10−9 m2 min−1 with increasing concentrations of Tween-80 from 1000 mg L−1 to 5000 mg L−1. The PVA-SA-PHB-AC composite carrier demonstrated great scope for immobilizing microorganisms for practical wastewater bio-treatment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39837.