Linguistic researches posit that discourse has a complex structure consisting of semantic relations and hierarchies, but this construct has remained relatively undefined in phonetic and psycholinguistic studies. In the current thesis, through seven experiments, we investigated the prosodic features and comprehension process of discourse structure from the perspectives of relation and hierarchy. First, we conducted four experiments to investigate the prosodic signaling of hierarchy and relation in Chinese discourse. The first two experiments explored the relationship between prosodic variation and hierarchy structure in discourse. It was found that speakers realized longer pauses and higher f0 max at boundaries of higher hierarchy. Also, we found that the influence of hierarchy on prosodic features was consistent across speakers. In the third experiment, we investigate whether the acoustic features of discourse focus were subjected to the influence of discourse hierarchy. The results revealed that foci embedded higher in the discourse hierarchy had relatively longer duration and more expanded pitch range. In the fourth experiment, we investigated whether topic relation affect the prosodic features of discourse. It was found that compared with topic continuation relation, topic shift relation induced higher f0 max and f0 min. Then, we investigated whether semantic hierarchy and relation played a role in discourse comprehension. In Experiment 5, the role of hierarchy in discourse comprehension was investigated. It was found that target words in the high hierarchy condition elicited a larger N400 effect compared with those in the low hierarchy condition. In Experiment 6, we explored the effect of topic relation in discourse comprehension. It was found that reading times for the target clause were significantly longer in the topic-shift condition relative to the topic-continuation condition. However, in Experiment 7, when the discourse comprehension task was changed to the word recognition task, the effect of topic-shift disappeared. These studies together suggest that relation and hierarchy of discourse affect prosodic features and comprehension process significantly. With regard to prosodic features, hierarchy significantly influences timing and the pitch parameters while relation significantly affects pitch parameters. With regard to comprehension process, both hierarchy and relation affect comprehension process by modulating cognitive resources: information in higher hierarchy or information occurred after topic shift requires more cognitive resources to be processed.