In this paper using the polar semiconductor in a magnetic field , the first excited state (ES) Landau level add a zero- phonon state is degenerate with the ground state (GS) Landau level add one longitudinal optical (LO) Phonon state at ω_0-ω_c , ω_c is the cyclotron frequency. The purpose of in this paper is to investigate the pinning effect in a GQD in two dimensions using the improved Wigner -Brillouin Perturbation theory (IWBPT) .Since Gaussian quantum dot has two parameters to play important role namely the depth and range. One would expect much richer pinning behavior in GQD. We apply our calculation to GaAs and InSb in QD.