Objective To study Chinese medical pattern distribution of polymyositis（PM）and dermatomyositis（DM）.Methods Staging

typing and pattern identification were done to 80 patients.Results The incidence rates of qi deficiency

yin deficiency

blood stasis

phlegm-damp and fire-heat patterns were 60.0%

56.3%

63.8%

75.0% and 86.3% respectively.Three-pattern combination was common in form especially phlegm-heat-stasis pattern.The incidence rate of blood stasis pattern at active stage was higher than that at stable stage.The incidence rates of qi deficiency pattern and yin deficiency pattern at active stage were lower than those at stable stage.The incidence rate of yin deficiency in serious cases was higher than that in slight ones.Conclusion Combination patterns are common in PM and DM such as fire-heat

phlegm-damp

blood stasis

qi deficiency and yin deficiency

and has certain relevance to stage and type.