By establishing the near-field and far-field models of the diode laser arrays with the "Smile" effect, and combining optical near-field scanning method with Gaussian beam propagation theory, the conclusion that the value of "Smile" effect and the distribution decide the beam quality of diode laser arrays together is proved theoretically and experimentally. Except that, the beam parameters products of diode laser arrays under different "Smile" effect in the fast axis are calculated.