By detecting the Second Harmonic Generation (SHG) from the metal surfaces of Ag and Al via changing the polarization of incident light, we studied the surface nonlinear polarized source of these metals. It is found the phonomenological parameter "a", that Eudnick and Stern introduced in, to decribed the contribution of the second order surface current perpendicular to the metal surface, should lie between - 2 and - 7 (SH wave length: 0.532 μm). The value is of fairly different from the previous calculated experimentally measured ones. Our results also demonstrate thai the value of “a” changes with the incident angle, and the value of parameter “b”, describing the contribution of the parallel surface second order current of the metal, is experimentally proved, for the first time, to be —1 thatt theoretioal calculation tells ns.