Abstract: Objective To explore the distribution and influencial factors of posttraumatic stress disorder(PTSD)in medical pharmacy university students.Methods Undergraduates in Guangzhou city were selected with cluster sampling and interviewed with PTSDSymptom Chesk list(PCL-C)and self-designed questionnaire.T test,Logistic regession were used for data analysis.Results In 1081 medical undergraduates,the rate of PTSD positive symptom was 16.6%.The students with traumatic event exposure had higher PCL-C store than the students without the exposure(P<0.05).The average score of PCL-C w as not sigm ificantly different between sex(P>0.05).But there was a significant difference between grades and between specialties(P<0.05),respectively.Different specialty,suffering from sexual harassment or infringement,suffering from a ttacking,viciously slander,beating,family pressure,employment pressure,in terpersonal relationship pressure,environment maladaptation were the influential factors of PTSD.Conclusion PTSD is prevalent among undergraduate in Guangzhou city and effective measure should be taken.