Objective To explore the effects of cognitive-behavioral therapy for insomnia (CBT-I) on sleep quality and anxiety in insomnia patients with anxiety symptoms, and the mediating role of subjective insomnia cognition in sleep quality and anxiety. Methods A total of 141 insomnia patients with anxiety symptoms were enrolled. All participants received 8-week CBT-I and were assessed at baseline and after treatment with the Pittsburgh sleep quality index (PSQI), Hamilton anxiety scale (HAMA), insomnia severity index (ISI), and brief version of dysfunctional beliefs and attitudes about sleep scale-16 (DBAS-16). Results (1) The dropout rate was 14.2% (20/141). (2) The scores of PSQI and its sleep indexes, HAMA, ISI, and DBAS-16 were improved after treatment compared to the baseline (all P < 0.001). (3) Correlation analysis showed that PSQI scale decreased rate (PSQI_DR), HAMA decreased rate (HAMA_DR), ISI scale decreased rate (ISI_DR), and DBAS-16 increased rate (DBAS-16_IR) were significantly correlated with each other (all P < 0.01). (4) The mediation effect analysis was conducted with PSQI_DR as the independent variable, HAMA_DR as the dependent variable, ISI_DR and DBAS-16_IR as mediator variables. The Results showed that the mediation effect of ISI_DR (PSQI_DR→ISI_DR→HAMA_DR) accounted for 27.53% of total effect (r＝0.128, 95% confidence interval [95%CI] 0.028-0.250), and the chain mediation effects of DBAS-16_IR and ISI_DR (PSQI_DR→DBAS-16_SR→ISI-DR→HAMA_DR) accounted for 7.96% of total effect (r＝0.037, 95%CI 0.003-0.103). Conclusion CBT-I can improve the sleep quality and anxiety of insomnia patients with anxiety symptoms. The improvement of sleep quality can positively predict the reduction of anxiety, and sleep beliefs and attitudes, as well as subjective insomnia severity play a chain mediated role in this process.