Objective To study the intestinal mucosal state of ulcerative colitis (UC) through UC endoscopic scores and to investigate the correlation between the endoscopic scores and clinical activity and histological scores. Methods A retrospective analysis was performed on data of 152 patients who underwent colonoscopy or sigmoidoscopy in Nanjing Drum Tower Hospital from January 2014 to September 2019. The results were graded with 7 endoscopic scores, namely, Mayo endoscopic score（MES）, modified Baron score（MBS）, endoscopic activity index（EAI) , Sutherland index（DAI or UCDAI) , Rachmilewitz endoscopic index（REI）, Lemann endoscopic index (LEI), and ulcerative colitis endoscopic index of severity（UCEIS）. Spearman correlation coefficients between endoscopic score and partial Mayo scores, Truelove-Witts disease severity score and Nancy index (NI), Robarts index (RHI) and Geboes score (GS) were calculated respectively. Consistency of each endoscopic score among different observers was analyzed. Results Except for the weak correlation between DAI and Truelove - Witts classification (r= 0.469, P < 0.001), all other endoscopic scores were moderately positively correlated with clinical activity scores with significance( all P＜0.001). However,the correlation between 7 endoscopic scores and histological scores was weak (P<0.001). Except that the consistency of MBS among observers was medium, those of MES, DAI and LEI among observers were poor, and those of UCEIS, EAI and REI among observers were worse (P＜0.001). Conclusion Endoscopic scores were moderately correlated with clinical activity indexes and weakly correlated with histological scores. However, patients with endoscopic remission may have histologic inflammatory activity, so attention should be paid to histological mucosal healing after endoscopic remission. The consistency of all 7 endoscopic scoring stystems among observers was low, and the repeatability was poor.