Abstract: Nanyin vocal music, mainly touched up with the pronunciation of Quanzhou dialect, consists of six pronunciations, wen (textual), bai (vernacular), fang (dialectal), guan (lanqing Mandarin), ancient (ancient pronunciation) and external (non-Han). Among them, "lanqing Mandarin" is the most distinctive. It sounds just like Mandarin but not the standard Mandarin, and the lingering charm of distinctive pronunciation and diction remains in ancient Nanyin music. The research on the unique pronunciation and the method of diction and resonance in lanqing Mandarin can not only provide the theoretical basis for Nanyin vocal music or its teaching, but also provide a practical path for its singing.