Mr. Zhao Yiheng, Institute of Semiotics-Media Studies, Sichuan University, pointed out that intentional meaning, textual meaning and explanatory meaning constitute three links of symbol expression, and an incomplete symbol is a symbol missing one of the three links. Intentional meaning is "possible" meaning, textual meaning is "should have" meaning, and the explanatory meaning provided by the receiver is "realizable" meaning. The description of symbolic process is ideal. Semiotics is complicated because a large number of symbols do not meet this minimum standard and can only be called "incomplete symbols". In fact, none of the three links is indispensable, and a large number of symbolic behaviors have not actually completed these three links, and one or even two links are missing.