Abstract-In this paper, 0 -→0 + first forbidden β-decay matrix elements have been calculated. For [206][207][208][209][210][211][212][213][214] Bi transitions relativistic M ± (ρ A ,λ=0) and nonrelativistic M ± (j A ,κ =1,λ=0) matrix elements have been calculated. In this calculations, the eigenfunctions and eigenvalues of Schrodinger equation solved by the more realistic Woods-Saxon potential have been used. The dependence of the radial parts in the matrix elements on the parameters (r 0 : the radii of nucleus, η: isovector parameter, r c : Coulomb radius and χ diffusion parameter) of Woods-Saxon potentialhas been investigated.