A stool flushing device having a control switch and a locking assembly comprises: a casing having a receiving space therein; the casing having an inlet which can be connected to a water source; the inlet being communicated to the receiving space; the casing having a first outlet and a second outlet; a rotary button being a disk like structure; an axial rod being connected to a lower center of the rotary button; a control portion separating the receiving space; the control portion including an upper disk, a valve disk and a lower disk; the upper disk being formed with a first injection opening and a second injection opening; the first injection opening being communicated to the first outlet and the second injection opening being communicated to the second outlet; the lower disk having a third injection opening and a fourth injection opening.