The analyses of second harmonic generation (SHG) effects have been firstly conducted for characterizing ultrashort pulse with the spectral phase interferometry for direct electrical reconstruction (SPIDER). The results show that we should multiply a modulation function for the recorded interferometric intensity in order to avoid the effect of bandwidth of the pulses, thus we can exactly reconstruct the fundamental-pulse intensity. The root-mean-square (RMS) phase error generated by bandwidth is proportional to the nonlinear-crystal length, the intersection angle of the beams. We can also obtain greater phase-matching acceptance angle in type II phase-matching crystal.