Seven absorption group-bands (1D2, 1G4, 3F2, 3F3, 3H4, 3H5, 3F4) of Tm3+ in YVO4 single crystals have been observed in the orientation absorption spectra recorded in the spectral range from 200 to 4000 nm at 300K.The integrated absorption cross section for each group-band was accurately evaluated. On the assumption that the anisotropy of this uni-axial crystal is small, the Judd-Ofelt theory was extended for the calculation of 4f-4f transition intensities of Tm3+ in YVO4. Two sets of phenomenological intensity parameters were derived from a least-squares-fit procedure.For c-axis cut sample we haveΩ2=10.18 (10-20cm2), Ω4=1.96 (10-20cm2), Ω6=0.75 (10-20cm2).For a-axis cut sample we haveΩ2 = 8.20 (10-20cm2), Ω4 = 2.47 (10-20cm2), Ω6 = 0.91 (10-20cm2).The anisotropy of the optical absorption intensities of Tm3+:YVO4 was theoretically analyzed in detail.