This study demonstrated the physiological and psychological effects of Cognitive Behavioral Therapy for Insomnia (CBT-I). CBT-I is an evidence-based psychotherapy that deals with bad sleep habits and behaviors, dysfunctional beliefs, and attitudes toward sleep. In this study, participants who did not have other mental illnesses or sleep problem related to sleep apnea of circadian rhythm sleep disorder and showed an insomnia severity index of 15 or more and Pittsburgh sleep quality index of 6 or more were recruited. They were randomly assigned to a treatment or a wait-list control group. The treatment group received six 60-min sessions of CBT-I (n=8), while the wait-list control group received not any psychological intervention(n=9). To verify the effectiveness of CBT-I, we measured the resting quantitative EEG and heart rate variability, insomnia symptom by self-report sleep scale and sleep monitoring data by smart wearable devices and sleep diary before and after treatment Results showed significantly decreased Beta power, sleep scale score and increased Theta power, WASO(Wake After Sleep Onset), SE(Sleep Efficiency), Sleep satisfaction. This study found that daytime hyperactivity can be reduced by psychological intervention. In addition, it is significant thatl the improvement of sleep problem were observed by using not only subjective self-report but also objective measures such as resting quantitative EEG and smart wearable devices.