The present invention relates to bicyclic tetrahydrofuran derivatives of Formula (1) and a preparation method thereof, and particularly it relates to a process of preparing compounds of Formula (1) by performing an intramolecular cyclization of tetrahydrofuran-allenol derivatives in the presence of alcohol compound, transitional metal catalyst and carbon monoxide: wherein n is 1 or 2; R is phenyl optionally substituted with C1-C6 alkyl, C1-C6 alkoxy, hydroxyl or C1-C6 hydroxyalkyl group; and R1 is C1-C6 alkyl group.