POJ (Pe'h-oē-jī), which is also called as Church Romanization, is the most traditional Taiwanese writing system that produces most articles. It is also one of the phonetic alphabet. In addition to the basic properties and written formats of the POJ, this paper also discussed the main POJ text processing procedure for Text-to-Speech, including POJ to numbered POJ conversion, Initial/Final segmentation, and tone sandhi processing. Moreover, we also provide a simple review on the previous development of Taiwanese Text-to-Speech systems.