Piezoelectric micromachined ultrasonic transducers (pMUTs) have been investigated as a promising new approach for ultrasound generation and reception. Most of the reported pMUTs employs a unimorph structure of a micromachined piezoelectric thin film on a silicon membrane. In this paper, a dome-shaped model for piezoelectric micromachined ultrasonic transducer (pMUT) was proposed to replace the conventional unimorph structure. A finite element analysis was carried out to study the elecro-mechanical behaviour of the dome-shaped model. The result showed that a considerable improvement of electro-mechanical coupling performance was achieved with the new model.