The following two questions have long been much discussed: 1. Are there both perfective aspect and past tense in Old Chinese? 2. Do the voiceless-voiced alternation and non-falling-falling variance in materials with variant pronunciations mean perfective aspect or past tense? Starting with such examples as Jie（解）and Zhu（著）which boast the features of voiceless-voiced alternation and non-falling-falling variance, this paper finds that these two features both express the meaning of “completion” but with different emphases. One emphasizes the state following the action completion and the other one emphasizes action completion before a reference point. In light of the latest research results on tense and aspect category in modern linguistics (For instance, some research scholars on English point out that past tense usually takes the utterance time as the reference point, but this view can not account for some linguistic phenomena, and actually past tense is relative to deictic center), we can see that Old Chinese expresses perfective aspect through voiceless-voiced alternation, for example, “Jie（解见上-匣上）”,“Zhu（著知入-澄入）”,“Bai（败帮去-並去）”,“Huai（坏见去-匣去）”,“Shu（属章入-禅入）”,“Zhe（折章入-禅入）”,“Juan（卷见上）/Juan Juan Quan（卷蜷拳群平）”,“Jin（尽精上-从上）”,“Hui（会见去-匣去）”,“He（合见入-匣入）”,“Ji（戢庄入） /Ji（集从入）” etc, and we also can see that past tense through non-falling-falling variance, for example, “Guo（过见平-见去）”,“Ran（染日上-日去）”,“Guan（贯见平-见去）”, “Liang(量来平-来去)”, “Chen(称昌平-昌去)”,etc. In conclusion, there is clear correspondence between phonetic form and grammatical meaning, and they should not be mixed with each other. The pronunciations of both the voiced initials of voiceless-voiced alternation and the falling tone of non-falling-falling variance boast additonal noun meanings and serve as attributes and adverbials, but have different manifestation forms: 1. The additional noun meanings of the former refer to things with the feature of a certain state. For instance, “Shu(属禅入)” refers to things that are joined together; The additional noun meanings of the later often record the results of action completion. For instance, the product of action completion of “Zhi(织)” is called “Zhi(织去声)”. 2.The former serves as attributes with the emphasis on the state following the action completion. For instance, “She Yang(折浊疡)”means the state of fracture after the action of breaking-off; The later serves as attributes with the emphasis on the action occurring and completing before a reference point. For instance, “Xuan Shi(选去声士)”means selecting the better ones from talents, and the action of selecting occurs before the completion of “Xuanshi”.3. It’s more common that the former functions as adverbials and refers to the state following the action completion, such as “Tong-Tong（通-同）”,“Bing-bing（并-並）”; The later generally serves as adverbials without state meaning and is more similar to pronunciation variance resulted from grammaticalization, like “Geng（更）”，“Chong（重）”，“Fu（复）”. Therefore, it is necessary to distinguish them from each other.