To capture the EEG components generated by the brain in judging traditional Chinese and western medicine propositions using event related potential(ERP) technique，explore the brain neural mechanism in understanding different medical propositions，and provide evidence for studying the thinking difference between traditional Chinese and western medicine at the cognitive neuroscience level.Methods:The EEG data of students majoring in traditional Chinese medicine(TCM) in understanding traditional Chinese and western medicine propositions were collected by suffix paradigm and sentence correctness judgment task.Repeated measures ANOVA was used to analyze the early left anterior negativity(ELAN)，P200，N400 and P600 time windows.Results:In ELAN and P200 time windows，there was no significant difference between the amplitudes of traditional Chinese and western medicine propositions(P>0.05).In N400 time window，western medicine propositions induced more negative amplitudes than TCM propositions(P=0.04).In P600 time window，TCM propositions elicited more positive amplitudes(P=0.01) than western medicine propositions.Conclusion:In the early stage of word recognition in proposition processing，western medicine propositions have more specific effect than TCM propositions.In the later stage of semantic integration，TCM propositions involve more integration processing than western medicine propositions.These may reflect the metaphorical mapping of TCM language.