Objective To explore the characteristics of the image parameters of tongue diagnosis of coronary heart disease with phlegm and blood stasis syndrome. Methods A total of 108 patients with coronary heart disease were enrolled. According to the syndrome differentiation criteria

48 patients were divided into an intermingled phlegm and blood stasis group and 60 patients in a blood stasis group. The ZBOX-I tongue-and-pulse image digital acquisition analyzer developed by Shanghai University of Traditional Chinese Medicine was used to collect the tongue images of the 2 groups of patients and extract the characteristic parameters including the tongue color（ the whole tongue

the root

the middle

the tip

the left part and the right part）

the tongue body shape

and tongue coating color（ the whole tongue coating

the root

the middle

the tip

the left part and the right part） and the tongue coating character.The tongue color included the red component R value

the green component G value

the blue component B value of the RGB color space

and the hue H value

the saturation S value

and the brightness V value of the HSV color space; the tongue body shape mainly includes fat and thin

crack index; Tongue coating color includes the R

G

B values of the RGB color space

and the H

S

and V values of the HSV color space; the tongue coating character mainly includes the thickness

greasy

and the peeling index. Results The G and B values of the tongue color component of the whole tongue and part of the tongue in the patients of the intermingled phlegm and blood stasis group were higher than those of the blood stasis group

and the S value was lower than that of the blood stasis group

and the H value of the whole tongue was smaller than that of the blood stasis group

and the R and V value of the tongue root was greater than that of the blood stasis group

and the H value of the tip of the tongue was lower than that of the blood stasis group（ P < 0. 05）. The tongue coating component G and B values of the whole tongue coating and each part in the patients of the intermingled phlegm and blood stasis group were higher than those of the blood stasis group

and the S value was lower than that of the blood stasis group（ P < 0. 05）. The R

H and V values of the tongue coating color in the root of the tongue were greater than in the blood stasis group

and the H value in the middle of the tongue coating was greater than that in the blood stasis group（ P < 0. 05）. The tongue body fatness and thinness index of patients in the intermingled phlegm and blood stasis group were higher than those of the blood stasis group（ P <0. 01）. There was no significant difference in the tongue body shape and tongue character parameters between the 2 groups（ P > 0. 05）. Conclusion Patients with coronary heart disease and the intermingled phlegm and blood stasis syndrome have more sever cyanosis

but lighter color. The color of the tongue coating is more bluish yellow

but paler and lighter. The green component G value

the blue component B value and the saturation S value in the tongue image parameters can be used as the objective indicators for differentiating the intermingled phlegm and blood stasis syndrome and the blood stasis syndrome in the coronary heart disease.