Effective oral expression is essential in the teaching profession. The “Chinese Phonology and Speech” course in Taiwan is pivotal in the elementary school teacher training curriculum, focusing on Mandarin pronunciation. However, challenges arise as elementary pre-service teachers often exhibit deviations from standard Mandarin pronunciation. There are also discrepancies between the pronunciation emphasis in the teaching materials and errors made by elementary pre-service teachers. This study examined the types and proportions of Mandarin pronunciation errors among 186 elementary pre-service teachers who took the “Chinese Phonology and Speech” course. We adopted a survey research approach using the “Mandarin Oral and Expressive Ability Test” and the “Mandarin Pronunciation Classification and Marking Table,” involving recording, transcription, and analysis. Results indicate that the highest rates of pronunciation errors occurred in phonological changes (16.57 %), tone (13.01 %), vowels (9.19 %), and initial consonants (3.13 %). Common issues included a lack of understanding regarding articulation positions and methods of initial consonants, vowel structures, tonal pitch, and phonological change rules. To address these challenges, we recommend integrating practical speaking exercises alongside the theory of national pronunciation to provide sufficient practice for elementary pre-service teachers. This research provides valuable insights into Mandarin pronunciation issues faced by elementary pre-service teachers. We provide recommendations for enhancing Mandarin pronunciation teaching in the elementary school teacher training curriculum while contributing to the education of future elementary school teachers.