Purpose : We found that when melting a frozen rabbit vitreous body, the gel structure is broken to be liquefied easily, and the gel-sol transition phenomenon occurs. This is almost like the liquefaction of the vitreous body in vivo. We try to clarify the liquefaction phenomenon by using this animal model. Methods : The vitreous body of rabbit is observed by double staining to reveal three-dimensional meshwork structure. After liquefaction, soluble non-collagenous substances and insoluble fiber aggregates were analyzed by amino acid analysis and GAG analysis. The major spots of soluble proteins of vitreous body and lens by 2D gel electrophoresis were analyzed by MALDI-TOF MS to determine peptide according to Mascot Search. Results : The native vitreous body has three dimensional meshwork structures. After liquefaction, the structure is changed into two parts, namely soluble non-collagenous beads and fiber aggregates. The farmer is crystallin family including αA-crystallin which is a major component of the lens and the latter is collagen and hyaluronic acid. Conclusions : The vitreous body has the three-dimensional structure of collagen and hyaluronic acid reinforced by crystallin. The liquefaction is induced by detachment of crystallin resulting in release of watery liquid from the meshwork.