Based on first principles within the density-functional theory, we establish three different concentration Eu-doping anatase TiO2 models by using the plane-wave ultrasoft pseudopotential method. We calculate the density of states, the electron density difference, the band structure and the absorption spectrum. The results show that Eu creates an impurity level in the band gap of TiO2 and a redshift in absorption spectrum of anatase TiO2. By comparing the bands of anatase TiO2, with two different Eu-doping concentrations (1.39 at% and 2.08 at%) we find that more Eu atoms make the impurity level deeper, the recombination rate bigger, and the electron lifespan shorter.