The Pegon script is part of the richness of the Sundanese language. The state of the Sundanese spelling in the Pegon script is an arbitrary writing system. This study aims to obtain a spelling structure in the form of the Pegon script used to write Sundanese. The source of the data used is a text of praise entitled "Nadhomul Mawalidi wal Mi'raj". The research method used is descriptive analysis with data collection techniques, documentation and literature study. Based on the results of the study, it was found that the Pegon script contained in the manuscript had certain rules such as writing consonant characters, vocalizations, punctuation, consonant clusters, and vowel sequences. There are 31 consonant characters in this script: 25 characters can be middle spliced (80%) and 6 characters cannot be middle spliced (20%). Pegon's vocalizations have 8 types: 7 vowel markers and 1 sukun sign as a vowel remover. The punctuation found is the number 2 Hija'iyah to indicate full reduplication. Consonant groups in the script are written with vocalizations inserted. The vowel clusters obtained are 15 types and are made up of 5 letters.