The present application provides a metallocene compound, and a preparation method and application thereof. The metallocene compound of the present application includes a structure as shown in Formula a, where Ar is selected from a substituted or unsubstituted C6-C30 aryl; Cp′ is selected from a substituted or unsubstituted cyclopentadienyl, indenyl, or fluorenyl; X is at least one of halogen, substituted or unsubstituted C1-C30 alkyl, alkoxy, substituted or unsubstituted C2-C30 dialkylamino, alkenyl, and substituted or unsubstituted C6-C30 aryl; and M is a transition metal element. The metallocene compound is suitable for catalyzing a C6-C30 long straight chain α-olefin raw material and also a mixed long branched chain non-terminal olefin raw material, and may obtain a polymerization product with a target molecular weight according to demand.