本文利用古文字资料对上古汉语清鼻流音作了共时和历时两个层面的考察，结果表明：商周雅言中有送气清鼻流音*m̥ʰ-、*n̥ ʰ-、*ŋ̊ʰ-、*l̥ʰ-、*l̥hj-、* ̥rʰ-和不送气清鼻流音*m̥-、*n̥-、*ŋ̊-、*ŋ̊j-、*l̥-、* ̥r-；战国楚方言中保留的清鼻流音有*m̥-、*n̥-、*ŋ̊-、*l̥-、*m̥ʰ-、*n̥h-、*n̥hj-、*l̥h-、* ̥rh-；战国秦方言及战国晚期(公元前 3 世纪前后)至汉初雅言中所保留的清鼻流音有*m̥-、*ŋ̊-、*m̥ʰ-、*ŋ̊ʰ-、*ŋ̊j-、*l̥-、*l̥h-、*l̥hj-、*r̥-、* ̥rh-。上古汉语不仅鼻音是三分的格局，流音也是三分的。有些字的清鼻流音可能还有更早的来源，即来自复辅音*hN-、*hr-和*hl-。战国晚期以后有些清鼻流音字开始塞化或擦化，大约自西汉后期(公元一世纪)以来，汉语中的清鼻流音已经少有痕迹。
Based on unearthed manuscripts, this paper studies the history of voiceless nasals and liquids in old Chinese phonology. It shows that there was a set of aspirated voiceless nasals and liquids and a set of unaspirated voiceless nasals and liquids in the common language of Shang and Western Zhou Dynasty. The aspirated voiceless nasals and liquids were *m̥ ʰ-, *n̥ h-, *ŋ̊ ʰ-, *l̥ h-, *l̥ hj-, *r̥ h-, and the unaspirated voiceless nasals and liquids are*m̥ -, *n̥ -, *ŋ̊ -, *ŋ̊ j-, *l̥ -, *r̥ -. In Chu dialect, the voiceless nasals and liquids continued to exist in Warring States period. They were *m̥, -*n̥ -, *ŋ̊ -, *l̥ -, *m̥ ʰ-, *n̥ h-, *n̥ hj-, *l̥ h-, *r̥ h-. Voiceless nasals and liquids were preserved in the Qin dialect in Warring States period and the common language in late Warring States and early Han Dynasty. They were *m̥ -, *ŋ̊ -, *ŋ̊ h-, *ŋ̊ j-, *l̥ -, *l̥ h-, *l̥ hj-, *r̥ -, *r̥ h-. In ancient Chinese, both nasal and liquid were trisection. Some voiceless nasals and liquids probably came from complex consonants such as *hN-, *hr-, *hl-, and so on. Some voiceless nasals and liquids became aspirated voiceless obstruent initials or unaspirated fricatives respectively. The voiceless nasals and liquids are difficult to trace after the late Western Han Dynasty.