We propose a scheme utilizing mean-field approach to exhibits the switching effect in a symmetrical Bose-Einstein condensate triple-well potential. Our study shows that tunneling from the left well to the right well of a large number of atoms can be controlled by a small amount of atoms in the middle well. We also discuss the role played by the relative phase and the relation between the zero-point and the critical value of working range. The potential applications of our model are pointed out.