Nonlinear single crystals have extensive applications in the technology of Opto-Electronics and Photonics. The properties of these crystals can be varied by electron irradiation. In this paper, we are reporting the comparative results of second harmonic generation efficiencies of (KDP) Potassium dihydrogen phosphate singles crystals and doped KDP without electron irradiation and with electron irradiation. The SHG efficiency of these crystals is measured using the optical simultaneous multi-channel analyzer, at wavelength  = 532nm using the spectrometer at Karnataka University Dharwad. The electron irradiation is done in the Microtron center, Mangalore University. The samples of KDP are irradiated by pulsed electron beam energy 8.0 MeV, with an average beam peak of 20 mA, for graded doses of 635 Gy, 1300 Gy, and 1924 Gy. It is observed that SHG efficiency is increased after electron irradiation when compared to unirradiated KDP.