A metallocene catalyst for preparing a high molecular weight polyolefin and a preparation method thereof

A compound represented by following Chemical Formula 1:

• in above Chemical Formula 1,
• X is halogen, same to or different from each other,
• R1 is C6-20 aryl substituted with C1-20 alkyl,
• R2, R3 and R4 are independently hydrogen, halogen, C1-20 alkyl, C2-20 alkenyl, C1-20 alkylsilyl, C1-20 silylalkyl, C1-20 alkoxysilyl, C1-20 ether, C1-20 silylether, C1-20 alkoxy, C6-20 aryl, C7-20 alkylaryl, or C7-20 arylalkyl,
• A is carbon, silicon, or germanium,
• R5 is C1-20 alkyl substituted with C1-20 alkoxy, and
• R6 is hydrogen, C1-20 alkyl, or C2-20 alkenyl.