Using first-principles calculations, the different doping structures and electronic properties of Y atom on anatase TiO2(101) surface were carefully studied to improve the photocatalytic activity of the surface. The results show that when Y atom is adsorbed on stoichiometric anatase TiO2(101) surface, the most stable adsorption site is between two 3-fold coordinated oxygen atoms. Meanwhile, when Y atom on anatase TiO2(101) surface with subsurface oxygen vacancy, the most stable adsorption site is between two 3-fold coordinated oxygen atoms that neighboring subsurface oxygen vacancy. In contrast, when Y atom on anatase TiO2(101) surface with surface oxygen vacancy, the most stable adsorption site is on the top of 3-fold coordinated titanium that neighboring surface oxygen vacancy. The charge density results show that Y atom can be stably adsorbed on anatase TiO2(101) surface. Furthermore, the density of states results show Y doped on the surface with surface oxygen vacancy can suppress the band gap from 1.67 eV to 1.44 eV, and induce extra impurity energy levels, which cause a fractional transition of electrons and improve surface photocatalytic ability. This study provides theoretical support for enhancing the surface photocatalytic ability of TiO2 (101) by single atom Y doping.