The optical properties of biexciton and exciton states in strongly oblate ellipsoidal quantum dot are investigated in the framework of variational method. The trial wave function for the biexciton is constructed on the base of one-particle wave functions. The dependencies of the photoluminescence spectra for the crossover states of biexciton and exciton are constructed as a function of the incident light energy. The peak position of the photoluminescence spectra for biexciton and exciton are revealed. The oscillator strength of biexciton and exciton are calculated. The biexciton’s and exciton’s radiative lifetimes in strongly oblate ellipsoidal quantum dot are estimated.