In this research, the structural and optical properties were studied for Bi2O3 and Bi2O3: Al  thin  films  with   different  doping   ratios  ( 1, 2, 3 ) %  ,  which  were  prepared  by  thermal evaporation  technique under  vacuum , with  thickness  ( 450 ± 20 ) nm  deposited  on  glass substrates  at  room  temperature ( 300 ) K , Structural   measurements by ( XRD)  techniques demonstrated   that  all   samples  prepared   have  polycrystalline  structure   with  tetragonal structure and  a preferred orientation  [ 201 ]   the   optical  measurement shows that  all films have  a  direct  energy  gap  ,  and  in general  decrease   with   the   increase  of  doping  ratio except  ratio  ( 3% Al )  .  The optical constant such as absorption coefficient , extinction coefficient , refractive index real and imaginary parts  of the  dielectric constant  and optical conductivity  were calculated  before  and  after  doping  with  the  range  of  wave  lengths ( 300 - 1100 ) nm .