Objective To preliminarily discuss the clinical identification system of primary insomnia Yin or Yang syndrome. Methods Clinical epidemiological methods were adopted to investigate the social demographic characteristics

social factors and healthy factors

and other factors of 704 patients with primary insomnia. Neuropsychological scales were used to evaluate patients’ quality of sleep and psychological conditions. At the same time the sleep parameters were observed. Single factor and multi-factor binary Logistic regression analysis were used to analyze the main influencing factors of Yin or Yang primary insomnia. Results Among the 704 patients with primary insomnia

there were 525 cases of Yang Syndrome

and 179 cases of Yin syndrome. Compared with the patients with Yin Syndrome

patients with Yang syndrome were older

predominantly male

single

with type A personality

and smoking.Among the patients with Yang syndrome

scores of physical exercise intensity

high-quality protein and cholesterol intake

subjective self-assessment

religious beliefs

social support and contact

interest and hobbies were lower

and PSQI score was higher（ P < 0. 05 or P < 0. 01）; and they were showing obvious depression and anxiety state. Logistic analysis showed that the main influencing factors of Yin or Yang primary insomnia are age

gender

marital status

physical exercise

cholesterol intake

social support and contact

interests and hobbies

PSQI scale score

sleep time

arousal frequency

and sleep efficiency. Conclusion The majority of patients with primary insomnia are with Yang syndrome

among which liver depression transforming into fire syndrome and Yin-deficiency and fire-hyperactivity syndrome are more common. Patients with Yang syndrome are older

more single and male

and the intensity of physical exercise is lower. These patients also have low cholesterol intake

lack of social support and relations and interests

poor overall sleep quality

which is mainly manifested as short sleep time

higher arousal frequency and low sleep efficiency.