Within the theoretical framework of functional linguistics, this paper conducts analysis of linguistic features concerning doctor-patient discourse in clinic from three perspectives including ideational metafunction, interpersonal metafunction and textual metafunction. It testifies the feasibility of investigating this type of discourse from the perspective of functional linguistics. The language structure of doctor-patient discourse in clinic is decided by the social function it performs, which strongly shows the fact that doctor and patient struggle for the power via language. Functional linguistics provides insight in the study of doctor-patient discourse in clinic, and puts forward a few tentative suggestions as how to adjust doctor’s language strategy to construct new doctor-patient relationship.