In this article, hydrogels were prepared by compounding Polyvinylpyrrolidone (PVP) with Poly (vinyl alcohol) (PVA), which is used as artificial cartilages, by means of repeating freezing and thawing and irradiation, for improving their mechanical and Surface lubricative properties. The structures and properties, including gel content, crystallized degree, elastic modulus, and frictional coefficients of the compound hydrogels with different PVP contents and irradiative conditions, were examined and compared. The existence of PVP macromolecules interfered with the crystallization of PVA hydrogels resulted in the decrease of gel contents and elastic modulus, as well as the unstable external frictional coefficient in water. After irradiation treatment, these performances increased with irradiation intensity in lower dose ranges. The solubility and exudation of PVP in water were prevented and reduced because of the chemical crosslink of PVA and PVP, and the lubricative properties of PVA/PVP hydrogels in water were improved. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 736-741, 2009