Abstract: The power ultrasonics composite vibrator consisting of piezoelectric ceramics has many advantages, but for practical load, the match of the vibrator with the sound load is sometimes not good that the sound energy is low. It will be more difficult to radiate the sound energy out, if the piezoelectric ceramic pieces are not located correctly in the vibrator, thus the loss in the transducer will increase and the electro-acoustic efficiency decreases. The position of the ceramic pieces in the vibrator is discussed.