Cu50Zr42Al8　bulk　metallic　glass(BMG)　was　prepared　and　microstructure　of　Cu50Zr42Al8　tapered　sample　was　characterized　by　means　of　X-ray　diffraction,　differential　scanning　calorimetry　and　optical　microscopy.　The　relative　dimension　of　surface　amorphous　region,　center　crystal　region　and　transition　region　between　the　two　regions　on　different　section　of　the　tapered　sample　is　strongly　determinated　by　the　cooling　rate　of　solidification.　The　critical　diameter　of　the　bulk　glassy　alloy　Cu50Zr42Al8　is　up　to　4.8　mm.　The　φ4　mm　BMG　exhibits　high　compressive　fracture　strength　of　2260　MPa　with　elastic　srtain　of　2.0%　and　plastic　strain　of　0.4%.　The　mechanical　properties　of　Cu50Zr42Al8　bulk　metallic　glass　and　its　composite　containing　CuZr　and　Cu10Zr7　crystalline　phases　were　also　discussed.　The　φ5　mm　BMG　composite　exhibits　a　combination　of　high　compressive　fracture　strength　(1849　MPa)　and　yielding　strength　(1670　MPa)　with　elastic　strain　of　1.6%　and　plastic　strain　of　1.9%,　the　final　fracture　behavior　of　the　glass　is　controlled　by　competition　of　the　two　crystallizing　phases.