Good patient-provider communication and high level of trust can decrease patients' risk perception and promote their acceptability of medical risks.The extent to which communication can be effective may be distinguished by different levels of trust. The present study examined the effect of patient-provider communication and treatment outcome on patients' risk awareness, and explored the moderating effect of trust. This research adopted a paper-based scenario experiment with a 2 (communication: good vs. poor) x 2 (treatment outcome: good vs. poor) between-subjects design. Three hundred sixteen college students were enrolled. They were randomly assigned to four groups and instructed to read more information about the two independent variables. Finally, all participants finished the manipulation check (eight items), affect- and cognition-based trust scales (10 items), and risk awareness scales (eight items) by questionnaire. The results showed the positive interaction effects between communication and treatment outcome on patients' acceptance of uncertainties. Affect- and cognition-based trust had similar moderating mechanisms on the interaction effect of communication and treatment outcome on uncertainty acceptability, and different moderating mechanisms on patient risk perception. In clinical work, we should develop the strategy to improve patien-provider communication and trust to improve patients' acceptability of uncertainty.