Objective: Epithelial dysplasia of the esophagus and gastric cardia is precancerous lesion, including mild, moderate and severe levels. In 2000 year, WHO recommended to replace dysplasia with intraepithelial neoplasia. Mild and moderate dysplasia were classified as low-grade intraepithelial neoplasia (LIN). Cardia adenocarcinoma was suggested to be called esophageal-gastric junction adenocarcinoma. The risk of cancer development and the rule of time evolution were detected in esophagus and esophageal-gastdc junction LIN in high incidence area of esophageal cancer in Northern China, in an effort to provide scientific data for the prevention of esophageal cancer. Methods: Between October 2001 and October 2002, two townships of Cixian were chosen to carry out endoscopic iodine staining screening cohort study. The total population aged 0-85 was 22,016, of which 6,596 aged 40-69 (3257 males and 3339 females). Except for thoese with contraindications and those who refused to join the study, 3,506 cases were finally recruited in the study, and the screening rate was 53.2%. According to WHO criteria of the pathological diagnosis, the esophageal squamous epithelium with mild and moderate dysplasia and esophageal-gastric junction with mild dysplasia were classified into LIN groups (including 616 cases). The control group contained a total of 2,478 cases without precancerous lesions and free of cancer in endoscopic screening. Results: From June to September in 2008, the cohort was followed up and 174 cases were lost, with a follow-up rate of 95.0%. Follow-up was 3,970.7 person- years in the LIN group and 16,120.0 person-years in the control group.Carcinomous conversion rates were 251.7 and 68.2/per 100,000 person- years respectively in the LIN group and the control group. The median time in the two groups was 38 and 47 months, respectively. Compared with that of the normal population, the relative risk (RR) of LIN was 3.69 (95% CI=1.57-8.69, P=0.001). Conclusion: Population with LIN are at high-risk for esophageal cancer and endoscopic examination every year is absolutely necessary.