Objective: To explore the predictive value of baseline polysomnography (PSG) parameters on the efficacy of cognitive behavioral therapy for insomnia (CBT-I) in the treatment of chronic insomnia, and to clarify its clinical application value. Methods: Forty patients with chronic insomnia who visited the Sleep Medicine Center of the hospital from March 2024 to June 2025 were selected. All patients completed 8 weeks of CBT-I treatment and PSG monitoring before and after treatment. The correlation between baseline PSG parameters (sleep efficiency, wake time after sleep onset, and proportion of N3 sleep stage) and the improvement values of the Insomnia Severity Index (ISI) and sleep efficiency after treatment was analyzed. Multiple regression analysis was used to screen predictive factors of efficacy. Results: Baseline sleep efficiency (r=0.36, P<0.05) was positively correlated with ISI improvement value, wake time after sleep onset (r=-0.33, P<0.05) was negatively correlated with ISI improvement value, and the proportion of N3 sleep stage (r=0.29, P<0.05) was positively correlated with ISI improvement value. Multiple regression analysis showed that baseline sleep efficiency (β=0.27, P=0.03) and wake time after sleep onset (β=-0.24, P=0.04) were independent predictors of ISI improvement value (adjusted R²=0.17, F=5.12, P<0.05). Conclusion: Sleep efficiency and wake time after sleep onset among baseline PSG parameters can effectively predict the efficacy of CBT-I in the treatment of chronic insomnia, providing an objective basis for clinically screening treatment-sensitive populations.