Abstract: In the literature, the adverb "yiding" in Chinese has always been viewed as a modal item expressing both epistemic and deontic modality.In the present paper, we argue that this is not the case.We demonstrate that there are three uses of "yiding", viz."yiding₁" as an epistemic modal, "yiding₂" as a truth confirmer, and "yiding₃" as a modal intensifier.According to our observation, "yiding₃" can just co-occur with the strong necessity modals, but not with the weaker ones; and the occurrences of "yiding" in the latter circumstances have to be treated as "yiding₁" or "yiding₂".Moreover, we point out that the intensification of "yiding₃" would be induced by the precisification effects, which leads to the expansion of modal domains.