Objective To study the characteristics of peptic ulcer (PU) of korean nationality(KN).Method The 4842 cases of PU were detected by gastroscopic technique from Jan 1985 to Apr 1999.The patients were divided into Korean nationality(KN,n=3124) and Han nationality(NH,n=1718) groups,the difference of between two groups was compared and analyzed.Results The morbidity of gastric ulcer C(GU) in KN group was obviously higher than that of HN group,however,the morbidity of duodenal ulcer(DU) was lower in KN group.Morbidity of GU was signifcantly higher than those of DU in KN group.In contrary to KN group,it was lower in HN group.The moraibity of composite ulcer(CU) in KN group was significantly higher than those of HN group in the spring,but in the autumn,the CU morbidity of HN group was higher.PU morbidity of KN group in the spring and winter were markedly higher than those of HN group.The helicobacter pylori(HP) infective rate of the patients with PU in KN group was significantly higher than those of HN group.HP positive rate of the patients with DU was obviously higher than that of the patients with GU.The morbidity of ulcer in KN group was significantly higher than that in HN group at gastric antrum,gastric body,anterior wall of duodenal bulb respectively,but the ulcer morbidity of gastric angle,pyloric canal,greater curvative of duodenal bulb were higher in HN group than that in KN group.The morbidity of all types peptic ulcer in KN group was remarkable higher than that of HN group in age over forty.In constrast,under forty-age-old(or equal to forty),the PU incidence of those anatomical situs of KN group was lower than that of HN group.The average phathogenic attack age of all type ulcer in KN group were significantly higher than that in HN group.The morbidity of ulcer of gastric antrum and anterior wall of duodenal bulb were most in two nationality groups,the autumn was the most season in two nationality groups.Conclusions PU of KN has own characteristics in detectable rate,attack season,pathogenetic situs,age of PU attack as well as HP infection etc.