The current dissertation project examined the influence of orthographic experiences on the development of the functional phonological unit in spoken word production in native Mandarin-speaking children. Functional phonological unit refers to the first selectable phonological unit after lexical selection in the planning of spoken word production. Previous research has shown that the acquisition of orthographic knowledge restructures literate speakers’ phonological representation and in particular, the acquisition of alphabetic orthographic knowledge improves children’s phonological awareness at the phonemic level. However, few studies have investigated the influence of orthographic experiences on phonological retrieval and encoding in spoken word production. The goal of this dissertation is to fill this gap. Four experiments were carried out to conduct the investigation. Participants consisted of native Mandarin speakers from four age groups with different orthographic experiences, including 1) Grade 1 children, who were comparatively more exposed to alphabetic Pinyin and had very limited Chinese character knowledge, 2) Grade 2 and Grade 4 children, who had better character knowledge and more exposure to characters, and 3) adult readers, who had the highest level of character knowledge and the most exposure to characters. Experiment 1 investigated whether the onset served as the functional phonological unit in producing monosyllables; Experiment 2 investigated whether the role of the onset in phonological retrieval and encoding was sustained when producing disyllabic words; Experiment 3 examined the role of the syllable segment (i.e., a syllable whose tone is indeterminate or an atonal syllable) in producing disyllabic words; Experiment 4 examined the role of the tonal syllable (i.e., tonal information is also included) in producing disyllabic words. Results showed that only Grade 1 children selected the onset as the functional phonological unit regardless of the word length during spoken word production and that additionally, they might process the rime segment and tone as a cohesive unit. By contrast, Grade 4 children and adults selected the syllable segment as the functional phonological unit. Grade 2 children were in their transitional stage of development, and they selected tonal syllable as the functional phonological unit. The different orthographic experiences of the four groups might contribute to the above differences. The current dissertation has important theoretical and pedagogical implications. The aforementioned findings help us better understand the mechanism of phonological processing, and as a result, may help educators develop more efficient pedagogical approaches to improve children’s phonological processing ability.