Objective To explore the diagnosis rules of TCM syndromes of insomnia of the subhealthy patients with discriminatory analysis. Methods The data of 413 insomnia patients in a subhealthy condition were collected. A questionnaire on TCM syndromes of insomnia was worked out

which included 33 common symptoms of insomnia of subhealthy patients. The patients were differentiated into two syndromes

deficiency of both the heart and spleen （216 cases） and yin deficiency with fire flaring （197 cases）. The clinical symptoms were marked as "yes" and "no"

and scored as "1" and "0". According to the TCM syndromes of patients

the variables were step-by-step discriminatively analyzed

those significant contributors were attributed into the discriminant function formulas

and the uniformity of which were tested with returning-replacement and knife-cut methods. Results The 12 variables of significant contribution in differentiating the two syndromes were screened out as following: tinnitus

hot sensation in chest

palms and soles

red eyes

yellow urine

night sweating

constipation

dry throat

irritability with heartburn

tiredness

bitter taste in mouth

pale complexion

and palpitation. The discriminant function formulas were established as: Yin deficiency with fire flaring =-6.183 + 3.326 × red eyes + 1.511 × bitter taste in mouth + 1.887 × irritability with heartburn + 2.915 × tinnitus + 1.919 × dry throat + 3.017 × hot sensation in chest

palms and soles + 1.798 × palpitation + 0.965 × night sweating + 2.877 × tiredness + 1.069 × pale complexion + 2.025 × yellow urine + 2.141 × constipation; Deficiency of both the heart and spleen = -3.529 + 0.573 × red eyes + 0.762 × bitter taste in mouth + 1.070 × irritability with heartburn + 1.091 × tinnitus + 0.950 × dry throat + 1.851 × hot sensation in chest

palms and soles + 1.086 × palpitation -0.436 × night sweating + 3.712 × tiredness + 1.930 × pale complexion + 1.134 × yellow urine + 1.391 × constipation. The total uniformity examined by the returning-replacement step-by-step was 81.1%

and that calculated by knife-cut was 79.7%. Conclusion The discriminant function formulas of TCM syndromes of insomnia of the subhealthy patients match well with the clinical diagnosis. They are improving the accuracy and objectivity of TCM diagnosis.