As an important device for non-destructive testing (NDT), the air-coupled ultrasonic transducer has a broad application prospect, but duo to the low bandwidth (BW), low sensitivity (SNS, high two-way insertion loss (IL) and other defects resulted from the mismatch between piezoelectric element and air acoustic impedance, its application is limited. The preparation process of air-coupled ultrasonic transducer is optimized in this paper, and the dimension design of piezoelectric elements is simulated by using COMSOL. An air-coupled transducer with operating frequency of 400 kHz is fabricated through regulating the acoustic impedance of piezoelectric elements and air by using 1-3 piezoelectric composite elements with optimizing matching layers of epoxy resin+hollow glass beads.The transducer has a pure thickness at the operating frequency, a wide bandwidth, and sensitivity with a two-way insertion loss of -38 dB. The results show that the air-coupled ultrasonic transducer fabricated by the self-developed process has good performance and great application potential.