This paper presents a piezoresistive pressure microsensor composed of a Silicon on Insulator (SOI) layer with sensing elements (a pressure-sensitive diaphragm and four piezoresistors) and a glass cap for hermetic package. The pressure under measurement bends the pressure-sensitive diaphragm, producing resistance changes of underlining piezoresistors. Numerical simulations were conducted, where key structure parameters of piezoresistors were optimized, producing a sensitivity of 18.61 mV/(V·MPa) and a linearity of 0.74%FS. The proposed microsensor was fabricated based on simplified fabrications, which included only two etching processes and one anodic bonding. Compared to other microfabrications, the fabrication of the developed microsensor does not need ion implantation and thin-film deposition, leading to high uniformity with low residual stress. Fabricated microsensors were characterized, obtaining the sensitivity of 17.278 mV/(V·MPa) and the linearity of 0.613 %FS (0-2.5 MPa).