A high-valent phosphoniomethylidyne tantalum complex [(C 5 Me 4 H)Ta(C-PPh 3 )(CH-PPh 3 )Cl] (3) was obtained via transylidation reactions of (C 5 Me 4 H)TaCl 4 with 5 equivalents of the phosphorus ylide Ph 3 P=CH 2 . The addition of strong base Li(N(SiMe 3 ) 2 is beneficial to the transylidation reaction and improves the yield of complex 3. The ylide adduct complex [(C 5 Me 4 H)TaCl 4 (CH 2 PPh 3 )] (4) as the reaction intermediate was isolated through the reaction of (C 5 Me 4 H)TaCl 4 with one equivalent of the phosphorus ylide Ph 3 P=CH 2 . Both complexes 3 and 4 were structurally characterized by X-ray single crystal diffraction. A comparison on the preparation and properties of the phosphoniomethylidyne tantalum complexes with different supporting ligands, [CpTa(C-PPh 3 )(CH-PPh 3 )Cl] (1) (Cp = cyclopentadieneyl ligand), [(C 5 Me 4 H)Ta(C-PPh 3 )(CH-PPh 3 )Cl] (3) (C 5 Me 4 H = tetramethylcyclopentadienyl ligand) (3) and [Cp ⁎ Ta(C-PPh 3 )(CH-PPh 3 )Cl] (2) (Cp ⁎ = pentamethylcyclopentadienyl ligand) was discussed.