We measured the absorption/transmission performance of ZnO thin films doped with europium (Eu) and aluminum (Al). ZnO and Zn1-(y+0.01)(Al-0.01, Eu-y)O (y = 0.00, 0.01, 0.03 and 0.05) nano particles were synthesized using sol-gel method and covered on a soda-lime glass surface by spin coating. After annealing at 500 A degrees C, UV-Vis. measurements were performed in wavelength range of 300 and 800 nm to calculate the band gap of nano particles from the absorption/transmission performances. The resistivity measurements were employed to understand the relationship between band gap and DC electrical performance by Eu amount of each Zn1-(y+0.01)(Al-0.01, Eu (y) )O thin film. As a conclusion, after reaching a minimum value with 1 mol% Eu doping, a monotonic increase in band gap was observed by enhancing Eu amounts in Zn0.99Al0.01O lattice.