Cognitive semiotics is a new field for the study of meaning in trans-disciplines, such as semiotics, cognitive linguistics, and corpus linguistics. This paper aims at studying how cognitive semiotics is employed to construe conceptual metaphors in discourse. We conducted a corpus-based study, with Lakoff and Johnson’s Conceptual Metaphor Theory (CMT) and Fauconnier and Turner’s Blending Theory (BT), to illustrate our cognitive-semiotic model for metaphors in Dragon Seed, written by Nobel Prize winner Pearl S. Buck. The major finding is that metaphors are mental constructions involving many spaces and mappings in the cognitive-semiotic network. These integration networks are related to encoders’ cognitive, cultural, and social contexts. Additionally, cognitive semiotics can be employed to construe conceptual metaphors in discourse vividly and comprehensively and thus is helpful to reveal the ideology and the theme of the discourse.