【Abstract】Based on Halliday’s interpersonal function theory， this thesis carries out an analysis of the interpersonal meaning of the characters’ speech in the novel Tess of the D’urbevilles mainly from the aspects of modality system. The aim is to reveal characters’ attitudes toward each other， to infer their relationships and characteristics. It is hoped that the analysis of interpersonal meaning contributes to better interpret characters and understand this great work.
　　【Key words】metaphor of modality； interpersonal meaning
　　1. Metaphor of Modality
　　As a matter of fact， meanings made through modality can also be realized by a clause besides modal verb and modal adjunct. Halliday （2000： 354） refers to this kind of device employed in modality as the metaphor of modality， which is based on the semantic relationship of projection. He points out that the speaker’s opinion regarding the probability is coded not as a modal element within the clause but as a separate， projecting clause in a hypotactic clause complex. At the same time， Halliday suggests that the basic distinction that determines how each type of modality will be realized is the orientation， i.e. “the distinction between subjective and objective modality and between the explicit and implicit variants” （ibid： 357）. Thompson （2000： 60） names the orientation of modality as modal responsibility according to how far the speaker accepts responsibility for the attitude being expressed. In the interaction， if the speaker wants to express his or her personal judgment or inclination more explicitly， the more subjective orientation is indicated， e.g. “I think Mary is ill”. But in some cases，， the speaker might intend to conceal his or her personal viewpoint or assessment， and thus the more objective orientation is indicated， e.g. “It’s quite probable that Mary is ill”. There are four types of modal orientation： explicit subjective， explicit objective， implicit subjective and implicit objective， which are shown in the following Table .
　　Subjective： Explicit Subjective： Implicit Objective： Implicit Objective： Explicit
　　Modalization： probability I think [in my opinion] Tom knows Tom will know Tom probably knows [in all probability] It’s likely that Tom knows [Tom is likely to]
　　Modalization： usuality Fred’ll sit quite quiet Fred usually sits quite quiet It’s usual for Fred to sit quite quiet
　　Modulation： obligation I want John to go John should go John’s supposed to go It’s expected that John goes