By using angle-resolved photoemission spectroscopy(ARPES)combined with the first-principles electronic structure calculations,we report the quantized states at the surface of a single crystal 2H-TaSe2.We have observed sub-bands of quantized states at the three-dimensional Brillouin zone center due to a highly dispersive band with light effective mass along kz direction.The quantized sub-bands shift upward towards EF while the bulk band at Γ shifts downward with the decrease of temperature across charge density wave(CDW)formation.The band shifts could be intimately related to the CDW.While neither the two-dimensional Fermi-surface nesting nor purely strong electron-phonon coupling can explain the mechanism of CDW in 2H-TaSe2,our experiment may ignite the interest in understanding the CDW mechanism in this family.