The purpose of this study was to investigate how disclosing personal background knowledge (PBK) between Americans and Chinese interlocutors impacts their computer-mediated communication and their divergent thinking performance in solving a problem. In the study, 178 participants (67 American and 111 Chinese) were recruited from language classes at universities in the United States and China. Each participant was paired with another participant from the same cultural background (intracultural communication) or from the other culture (intercultural communication). After pairing with a partner, the dyads were separated into two groups: the PBK group and the No-PBK group. In the PBK group, the dyads completed a PBK exchange task and then discussed a social problem online through MSN (a popular instant messenger service). The No-PBK group discussed the social problem without doing the PBK exchange task. Divergent thinking performance was measured through an essay participants wrote individually, and the factors affecting the effectiveness of the communication were measured with a questionnaire. There were several major findings: (1) The Chinese participants showed a better divergent thinking performance in solving the problem after intercultural communication than after intracultural communication. (2) The Chinese participants after intercultural communication outperformed those after intracultural communication in terms of divergent thinking performance only when PBK was exchanged. (3) When PBK was disclosed, Chinese participants showed improved confidence in predicting their partner's behaviors in the communication. They also gained an appreciation for different views, better perceived good relationships, and improved social presence and trust with their American partners. (4) The qualitative analysis revealed that PBK exchange led the Chinese participants to have a more satisfactory and pleasant communication experience. The experience made the participants have a more effective task based communication and show better divergent thinking performance during problem solving. In addition, PBK exchange had little impact on the American participants. The implications regarding collaborating and communicating in an online intercultural environment and the design of a productive intercultural learning environment were discussed.