By optimizing the high frequency transducer design and extra thin piezoelectric film preparation technique, a BAW delay line same operated at K band has been fabricated in this work. The operating center frequency of 23.8 GHz, insertion loss of 51.9 dB, bandwidth of 1 122 MHz, delay time of 299 ns, feed through suppression (FTS) of 29 dB and triple transmitting suppression (TTS) of 40 dB have been achieved.