Abstract: This paper re-examines the pair terms of self and shift designation proposed in Zhu Dexi (1983) from the perspective of formal syntax and semantics. It’s found that the two semantic concepts have their problems, especially the term “self designation”, whose references do not form a natural class syntactically. It’s argued that self and shift designation should be replaced by noun complement clause (NCC) and relative clause (RC) in formal syntax. Furthermore, the essential difference between RC and NCC is their licensing condition. RC requires a semantic variable changing RC from a proposition to a one-place predicate. Semantically, RC and its head noun are calculated by predication modification. However, NCC is licensed by the head noun with the +CONTENT feature whose semantic type is <t,<e,t>>. The noun complement clause and the head noun is calculated by functional application. Finally, based on the source of semantic variable, RCs can be classified into RCs with a syntactic gap in the relative clause and those without a syntactic gap in the relative clause, corresponding to the head noun. The new classification of “XP de” based on formal syntax and semantics not only solves the problems of blurred boundaries between self and shift designations, syntactic heterogeneity within self designation, but also covers a large array of de-related phenomena and has a relatively strong predicative power.