Poly(vinyl alcohol) (PVA)/b-tricalcium phosphate (b-TCP, Ca 3 (PO 4 ) 2 ) porous composite, which has potential application in articular cartilage repair, was prepared through thermal foaming using water as both plasticizer and physical blowing agent. The effects of b-TCP content on the foaming behavior, the structure and properties of the porous composites were studied. The results showed that b-TCP could form hydrogen bonds or coordination interaction with PVA and water; with the incorporation of b-TCP, the content of nonfreezable bound water in system increased, the water evaporation reduced, beneficial to the controllable foaming of water. The interactions between PVA-b-TCP led to the enhanced melt viscosity of PVA. Simultaneously, the b-TCP particles in matrix could act as heterogeneous nucleation agent to increase the cell density. When b-TCP content was 7.4 wt %, the porous composite showed the optimal cell structure, i.e., 250 lm average cell size and 87% porosity. The dynamic modulus of the porous composites increased with b-TCP content and showed frequency-dependence. The surface contact angle and permeability of the porous composites varied with b-TCP content, which ranged from 358 to 488 and 11 3 10 214 to 27 3 10 214 m 2 , respectively. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44737.