Dysplasia of gastric stump mucosa in 47 cases was studies.Nuclear DNA contents were measured with an automatic imagie analysis system.The results showed that the mean values of the nuclear DNA contents,area,perimeter,maximum diameter,minimum diameter increased with the increase of severity of dysplasia in gastric stump mucosa(Plt;0.01);where as nuclear form factor decreased with the increase of severity of dysplasia in gastric stump mucosa(Plt;0.05).Severe dysplasia is similar to that of gastric stump cancer in the DNA ploidy histogram.Our results indicate biological behaviour of gastric stump mucosa dysplasia.This study suggests that DNA contents analysis may be used as an important reference for grading,screening,and treating dysplasia of gastric stump mucosa.