A spectral method based on B-spline functions is proposed for the numerical solution of the boundary layer flow of an Powell-Eyring fluid over a stretching sheet. First, the B-spline functions formula is represented, and the quasilinearization method is used to approximate the nonlinear equation of the problem with a sequence of linear equations. Then, the collocation method is used to approximate the answer of these equations and illustrate the relation between the shape parameters and the stream function using three various degrees of B-spline functions.