Abstract: There is a texttitled 参两 (controversially pronounced either as "can liang" or "san liang" in Chinese) in 正蒙 (pronounced as "zheng meng",a book by Zhang Zai,a thinker,educator and founder of Neo-Confucianism in the Northern Song Dynasty).Former Confucian scholars and sages have different opinions on the pronunciation and meaning of "参",which may be interpreted as "join,participate,together,etc.as in the Chinese phrase "参加",or as the number of three,identical to the ancient Chinese character "叁".In fact,Zhang Zai's theory of "参两" is first seen in横渠易说(pronounced as heng qu yi shuo in Chinese,another book by Zhang Zai),and later in正蒙.Through the analysis of the relevant items in 横渠易说 from two aspects of text dredging and theoretical interpretation,we can see that "参两" is not based on the theory of number,but on image,describing the lively life in the real world,which should be read as "参"(pronounced as "can" in Chinese) rather than "叁" (pronounced as "san" in Chinese,meaning three).Accordingly,参两 in正蒙should be pronounced as "can liang" in Chinese rather than "san liang".参两 is exhaustive in a deeper connotation,which is inseparable from "太极"（pronounced as "taiji" in Chinese,an important concept in the history of Chinese Taoist culture,which describes the state of universe）.Although "参" contains the meaning of "three",it actually has a richer meaning of "joining" or "participating".It vividly and concretely describes the meaning of the combination of one and two.That is to say,Zhang Zai's "太极" contains 乾坤(meaning heaven and earth).In essence,"太极" is a popular state of gasification and a dynamic picture.The relationship between "太极" and"参两" is that "参" is the qualitative nature of the gasification,and "两" is the motivation of the gasification of "太极".

Key words: Zhang Zai, 参两 (pronounced as "can liang" in Chinese according to the author of this paper), 太极 (pronounced as "taiji" in Chinese,an important concept in the history of Chinese Taoist culture), 天参 （pronounced as "tian can" in Chinese,a term of Neo-Confucianism）, 数（number）, 象（image）, 正蒙（zheng meng）, 横渠易说（heng qu yi shuo）