A composite based on poly(vinyl alcohol) (PVA) and gelatin (Gel) was prepared in the form of a miscible interphase by freezing-thawing method using vanillin as a new compatilizer. The chemical and physical properties of PVA/Gel/vanillin composite hydrogels with different reagent concentration, and reaction time were investigated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), tensile testing, and scanning electron microscopy (SEM). The results elicit that the formation of C=N Schiff base between Gel and vanillin may break the intrahydrogen bonding of Gel. Proper reaction time and more interactive groups result in optimal interhydrogen bonding between modified Gel and PVA so that the miscibility between two polymers has been improved. In addition, the PVA/Gel/V composite with the vanillin concentration of 0.20 g/mL and 2 h stirring exhibits a better compatibility and a higher tensile strength, which can be tailored for potential use in cartilage tissue engineering. (C) 2010 Wiley Periodicals, Inc. April Polym Sci 117: 3657-3693, 2010