Based on the nature of "Bu (不)+ N" structure, this paper divides the negative words in pre-Qin Chinese into two categories and five sub-categories according to the distinction of time and space, and combs the evolution of Chinese negative word system from Pre-Qin to modern Chinese. This paper also focuses on two problems: (1) whether "Bu(不) + N" is the negation of noun by the determiner "bu(不)", and whether there is no implied verb between "Bu(不)" and noun, nor is the noun used flexibly as a verb; (2) there are two sources of "MEIYOU(没有)" in modern Chinese, first from the negative sign of noun "WU (无)", then from the negative sign of verb "WEI(未)". Traditionally, the negation words of pre-Qin Chinese are divided into four categories: (1) The "Bu(不)" category, which means simple negation. (2) The"Wei (未)"category, indicating a negative attitude towards the past. (3) The "Fei(非)" category, which conveys negation of judgment. (4) The "Mo(莫)" category, signifying prohibition. Such classification, though comes with a certain degree of rationality, but embraces unscientific elements. For example, the "Bu(不)" category as a notion of simple negation is not a scientific explanation. This paper attempts to apply the research results of negative words in modern Chinese to the study of negative words in ancient Chinese. Professor Nie Renfa聂 仁发 (2001) believes that the time significance of the "Bu(不)" and "Meiyou(没有)" categories in modern Chinese is reflected in the "Object(体)" rather than "time （时）" and summarizes their differences as: "Bu(不)" ：【+Negation】[-Realization] Or“Mei(没)“：【+Negation】[+Realization] Professor Nie”s belief is truly inspirational. Hence we pursue further, by judging from the time elements of the pre-Qin Chinese negation word system, to try to divide them into two main categories as well as five small sub-categories. We shall be deeply obliged to receive feedbacks in any forms as well as criticisms as to determine whether this classification is appropriate, correct and in particular with reference to the negation of judgment as a [-Time elements]; while the negation of the imperatives as a [+Time elements].