In this paper, five kinds of power ultrasonic transducers with different section plane positions are designed and the shapes of the transducers are straight. The different section plane position changes with the length l2 of front cover. That is to say, the longer l2 is, the more front the position of the section is. The experiment indicates the great influence of the section plane position on the transducer performance.With the increase of the length of the front cover, the dynamic resistance reduces gradually, and the resonance frequency and the anti-resonance frequency also reduce. Under this condition, the anti-resonance frequency declines more sharply, and the mechanical quality factor increases gradually, but the effective mechanical and electrical coupling coefficient reduces gradually. The transducer has different measure targets in different situations. Therefore, different parameters may be primordially considered to be designed according to the actual use of the transducer in this paper. This provides the reference for manufacture and use of transducers.