midnight-noon ebb-flow theory in treating mild-to-moderate comorbid obstructive sleep apnea and insomnia（ COMISA）. Methods：A total of 96 patients with mild-to-moderate COMISA treated at Wenzhou Central Hospital from February 2024 to September 2025 were selected and randomly divided into a control group，an auricular acupoint group，and a time-selected auricular acupoint group using a random number table method，with 32 cases in each group. The control group received basic treatment. The auricular acupoint group received conventional auricular acupoint therapy in addition to basic treatment，while the time-selected auricular acupoint group received time-selected auricular acupoint therapy in addition to basic treatment. All three groups were treated for 30 days. Changes in polysomnography （PSG） parameters [Apnea-Hypopnea Index （AHI）， Hypopnea Index （HI）， Apnea Index （AI）， longest obstructive apnea duration， and lowest nocturnal oxygen saturation]， as well as Pittsburgh Sleep Quality Index （PSQI）， Epworth Sleepiness Scale （ESS），and Insomnia Severity Index （ISI） scores were observed before and after treatment. Results： After treatment，there were no significant differences in AHI，HI，AI，longest obstructive apnea duration，or lowest nocturnal oxygen saturation in the control group compared to before treatment （P＞0.05）. In the auricular acupoint group and the time-selected auricular acupoint group，AHI，HI，and AI decreased compared to before treatment（ P＜0.05）， longest obstructive apnea duration shortened （P＜0.05），and lowest nocturnal oxygen saturation increased （P＜0.05）. Both the auricular acupoint group and the time-selected auricular acupoint group showed lower AHI，HI，and AI（ P＜ 0.05），shorter longest obstructive apnea duration （P＜0.05），and higher lowest nocturnal oxygen saturation than the control group （P＜0.05）. There were no significant differences in AHI，HI，AI，longest obstructive apnea duration， or lowest nocturnal oxygen saturation between the time-selected auricular acupoint group and the auricular acupoint group （P＞0.05）. After treatment，there were no significant differences in PSQI，ESS，and ISI scores in the control group compared to before treatment （P＞0.05）. In the auricular acupoint group and the time-selected auricular acupoint group， PSQI， ESS， and ISI scores decreased compared to before treatment （P＜0.05）. Both the auricular acupoint group and the time-selected auricular acupoint group showed lower PSQI， ESS， and ISI scores than the control group （P＜0.05）. The time-selected auricular acupoint group showed lower PSQI， ESS， and ISI scores than the auricular acupoint group （P＜0.05）. Conclusion： Both time-selected auricular acupoint therapy and conventional auricular acupoint therapy can improve nocturnal hypoventilation， hypoxia， nighttime sleep quality， and daytime sleepiness in patients with mild-to-moderate COMISA，with no adverse reactions. In terms of improving nighttime sleep quality and daytime sleepiness， time-selected auricular acupoint therapy demonstrates superior efficacy compared to conventional auricular acupoint therapy.