This paper explores insomnia and chronomedicine from the perspective of the Midday-Midnight Circadian Qi Flow Na Zi Method. Chronomedicine is regarded as a “biological clock therapy”, among which the Midday-Midnight Circadian Qi Flow acupuncture method, based on the law of the ebb and flow of qi and blood at different times, opens and closes along the meridians and selects acupoints according to the time, which is an important manifestation of acupuncture chronotherapy. The Na Zi Method in the Midday-Midnight Circadian Qi Flow combines the circulation of qi and blood in the twelve meridians with the earthly branches, and conducts acupoint compatibility treatment in conjunction with the five elements’ generation and restriction, as well as the deficiency and excess of syndromes. As a common sleep disorder, insomnia is mainly characterized by the frequent inability to obtain normal sleep. Its basic pathogenesis is the malnutrition of the spirit and the imbalance of yin and yang, leading to the failure of defensive qi to enter yin normally. The treatment of insomnia mainly focuses on calming the spirit, communicating yin and yang, tonifying deficiency, and reducing excess. Clinical studies have shown that the use of Na Zi Method acupuncture, time-selected auricular point therapy, time-selected music therapy, etc., can significantly improve the sleep quality of insomnia patients, and the total effective rate is higher than that of conventional treatment methods. Chronomedical therapy provides new ideas and methods for the treatment of insomnia, which is conducive to unlocking the “time code” of insomnia and is worthy of further promotion in clinical practice.