Abstract: A 1.5-dimensional (1.5D) transesophageal echocardiography probe is designed and developed. Compared with the traditional 1-dimensional (1D) probe, the probe can achieve variable aperture and focus in elevation direction, thus improving the consistency of slice thickness in far field and near field. A 1.5D transesophageal ultrasonic probe with 320 elements is developed using traditional PZT-5H piezoelectric ceramics. The electrical properties, acoustic properties, and acoustic field distribution of the probe are tested. The measured center frequency and −6 dB fractional bandwidth of the 1.5D probe are 5.6 MHz and 76%, respectively. In the range of 5−70 mm, the slice thickness is 7−9 mm for 1D ultrasonic probe and 1.3−2.8 mm for 1.5D ultrasonic probe. The slice thickness difference is less than 0.2 mm in the range of 5−30 mm for 1.5D ultrasonic probe. And the information displayed by images is also more comprehensive and higher in resolution. Therefore, the 1.5D ultrasonic probe has a wider focusing depth, better distribution consistency in the near and far field, and higher spatial resolution.