Vitreous liquefaction is an age-related degenerative change, which will further alter the physicochemical properties of the vitreous and its surrounding tissues, resulting in various related eye diseases. The principal pathologic changes of that are the gradual depletion of hyaluronic acid and the collapse of collagen fibrillar network, with a series of biomechanical changes in vitreous body. This article reviews biomechanical properties of normal vitreous, the current measurements of these properties, formation mechanism and changes of biomechanics properties of vitreous liquefaction and correlation between synchesis and related ocular diseases, which provide insight into the ideas for the effective reduction and treatment of vitreous liquefaction.