This　paper　is　concerned　with　a　popular　form　of　Cahn-Hilliard　equation　which　plays　an　important　role　in　understanding　the　evolution　of　phase　separation.　We　get　the　existence　and　regularity　of　a　weak　solution　to　nonlinear　parabolic,　fourth　order　Cahn-Hilliard　equation　with　degenerate　mobility　M(u)　=　u(m)(1　-　u)(m)　which　is　allowed　to　vanish　at　0　and　1.　The　existence　and　regularity　of　weak　solutions　to　the　degenerate　Cahn-Hilliard　equation　are　obtained　by　getting　the　limits　of　Cahn-Hilliard　equation　with　non-degenerate　mobility.　We　explore　the　initial　value　problem　with　compact　support　and　obtain　the　local　non-negative　result.　Further,　the　above　derivation　process　is　also　suitable　for　the　viscous　Cahn-Hilliard　equation　with　degenerate　mobility.