This paper describes an investigation into the fabrication of absorber layer CuInSe2 films by co-evaporation process. And we used the stainless steel substrates to manufacture Al / ZnO:Al / ZnO /CdS / CuInSe2 / Mo / SLGTF / Stainless Steel(SS) flexible thin-film solar cell. The flexible solar cells were fabricated using soda-lime glass thin layers (SLGTL) as a diffusion barrier layer and an alkali source material deposited on various flexible substrates prior to the Mo backcontact layer deposition. Mo back contact layers were deposited by DC sputtering. The CIS absorber layers were grown by the two-stage process using a molecular beam epitaxy (MBE) apparatus. Then the CdS buffer layer was deposited by the chemical bath, RF sputter deposition of intrinsic ZnO and ZnO:Al (AZO) layer. Under the same process condition, using SLGTF as diffusion barrier layer improved open circuit voltage (Voc) 16.7% and short circuit current density (Jsc) 9.8%.