The effects of spontaneous and piezoelectric polarizations on the intersubband absorption in the GaN/ZnGeN2 quantum well are studied. Schrödinger and Poisson equations are solved self-consistently. The first order linear and third order nonlinear absorption coefficients of the intersubband transitions originating from ground and first excited states are calculated. We have presented the results relative to polarization, doping level and well length. The polarization causes the absorption peak to be reduced and shifted to higher energies, and the nonlinear absorption to become weaker, but this effect is slightly reversed with doping. The effect of polarization or doping increases with well length, but they are observed after 26 Å.