The nonlinear intersubband optical transitions in a quantum well with an applied electric field were studied, taking the effects of screening into account. The Poisson equation and the Schrodinger equation were solved self-consistently, and the intersubband electrooptical effect was then investigated when the quantum well was subjected to an externally biased electric field have been obtained. Both linear and nonlinear absorption coefficients and the refractive-index changes with the screening effects were calculated. Good agreement of the theoretical absorption spectrum with experimental results was found.