A metallocene complex represented by formula: wherein Ln is one of scandium (Sc), yttrium and the fifteen elements of lanthanides having an atomic number of 57-71; R 1, R 2, R 3, R 4, and R 5 are each independently selected from one of H, a C1-C20 alkyl group, a C1-C20 alkyl group containing an acetal group, a C1-C20 alkyl group containing a ketal group, a C1-C20 alkyl group containing an ether group, a C1-C20 alkenyl group, a C1-C20 alkenyl group containing an acetal group, a C1-C20 alkenyl group containing a ketal group, a C1-C20 alkenyl group containing an ether group, a C6-C20 aryl group, a C6-C20 aryl group containing an acetal group, a C6-C20 aryl group containing a ketal group, a C6-C20 aryl group containing an ether group, a C1-C20 silyl group, a C1-C20 silyl group containing an acetal group, a C1-C20 silyl group containing a ketal group, and a C1-C20 silyl group containing an ether group, or R 1 and R 2 are linked to each other to form a ring, or R 2 and R 3 are linked to each other to form a ring, or R 4 and R 5 are linked to each other to form a ring; E is O, S or N-R; said R is a methyl group, a benzene ring, or a substituted benzene ring; X 1 and X 2 are each independently selected from one of hydrogen, a C1-C20 aliphatic group, a C1-C20 alicyclic group, a phenyl group, a substituted phenyl group, a C1-C20 alkoxy group, a C1-C20 alkylamino group, a C1-C20 arylamino group, a C1-C20 silyl group, an allyl group, an allyl derivative, a borohydride group, and a halogen atom; said substituted phenyl group is a phenyl group substituted by one or more of a C1-C20 aliphatic group, a C1-C20 alicyclic group, and an aromatic group; L is a neutral Lewis base, and w is an integer of 0-3. wherein Ln is one of scandium (Sc), yttrium and the fifteen elements of lanthanides having an atomic number of 57-71; R 1, R 2, R 3, R 4, and R 5 are each independently selected from one of H, a C1-C20 alkyl group, a C1-C20 alkyl group containing an acetal group, a C1-C20 alkyl group containing a ketal group, a C1-C20 alkyl group containing an ether group, a C1-C20 alkenyl group, a C1-C20 alkenyl group containing an acetal group, a C1-C20 alkenyl group containing a ketal group, a C1-C20 alkenyl group containing an ether group, a C6-C20 aryl group, a C6-C20 aryl group containing an acetal group, a C6-C20 aryl group containing a ketal group, a C6-C20 aryl group containing an ether group, a C1-C20 silyl group, a C1-C20 silyl group containing an acetal group, a C1-C20 silyl group containing a ketal group, and a C1-C20 silyl group containing an ether group, or R 1 and R 2 are linked to each other to form a ring, or R 2 and R 3 are linked to each other to form a ring, or R 4 and R 5 are linked to each other to form a ring; E is O, S or N-R; said R is a methyl group, a benzene ring, or a substituted benzene ring; X 1 and X 2 are each independently selected from one of hydrogen, a C1-C20 aliphatic group, a C1-C20 alicyclic group, a phenyl group, a substituted phenyl group, a C1-C20 alkoxy group, a C1-C20 alkylamino group, a C1-C20 arylamino group, a C1-C20 silyl group, an allyl group, an allyl derivative, a borohydride group, and a halogen atom; said substituted phenyl group is a phenyl group substituted by one or more of a C1-C20 aliphatic group, a C1-C20 alicyclic group, and an aromatic group; L is a neutral Lewis base, and w is an integer of 0-3.