The behaviors of the ground-state energies and binding energies of the confined excitons in larger CdTe quantum dots(25—35nm) and the smaller CdS quantum dots(025—35nm) are studied variationally by means of the B-spline technique based on the effective mass approximation method. It is shown from the studie s that:(1) The ground-state energies and binding energies of the confined excito ns in the larger quantum dots are not sensitive to the barrier height of potenti al and the dielectric constant of surrounding material as compared to those of s mall quantum dots; (2) The behaviors of the ground-state energies and binding en ergies of the confined excitons in larger quantum dots are very different with t hose of smaller quantum dots (3)The B-spline technique is a better one to descri be the status of excitons confined by quantum wall or well, and this method is f it to calculate the multi-layer quantum dot accurately.