The stochastic model for the order parameter fluctuation in critical fluids is used to study time evolution of fluctuation spectrum in the quenched system. We focus on the effects of the long-range hydrodynamic interaction contained in the model on the fluctuation spectrum. Here we assume that in the absence of hydrodynamic interaction the fluctuation spectrum is known for which we take the results of Langer, Bar-on and Miller. The results are compared with the experimental fluctuation spectra of Goldburg et al. and Wong and Knobler, and excellent agreements are found for the peak heights and the peak positions when the quench depths are less than 2m°K.