Objective:To investigate the safety and feasibility of the CHESS endoscpic ruler (CHESS ruler), and the consistency between the measured values and the interpretation values by endoscopic physician experience.Methods:From January 2021 to January 2022, a total of 105 liver cirrhosis patients with portal hypertension were prospectively enrolled from General Hospital, Xixia Branch Hospital, Ningnan Hospital of People′s Hospital of Ningxia Hui Autonomous Region (29 cases), and the First People′s Hospital of Yinchuan (25 cases), General Hospital of Ningxia Medical University (18 cases), Wuzhong People′s Hospital (10 cases), the Fifth People′s Hospital of Ningxia Hui Autonomous Region (10 cases), Shizuishan Second People′s Hospital (6 cases), Yinchuan Second People′s Hospital (5 cases), and Zhongwei People′s Hospital (2 cases) 8 hospitals. The clinical characteristics of all the patients, including gender, age, nationality, etiolog of liver cirrhosis, and Child-Pugh classification of liver function were recorded. A big gastroesophageal varices was defined as diameter of varices ≥5 mm. Endoscopist (associated chief physician) performed gastroscopy according to the routine gastroscopy procedures, and the diameter of the biggest esophageal varices was measured by experience and images were collected, and then objective measurement was with the CHESS ruler and images were collected. The diameter of esophageal varices of 10 randomly selected patients (random number table method) was determined by 6 endoscopists (attending physician or associated chief physician) with experience or measured by CHESS ruler. Kappa test was used to test the consistency in the diameter of esophageal varices between measured values by CHESS ruler and the interpretation values by endoscopic physician experience.Results:Among 105 liver cirrhosis patients with portal hypertension, male 65 cases and female 40 cases, aged (54.8±12.2) years old, Han nationality 82 cases, Hui nationality 21 cases and Mongolian nationality 2 cases. The etiology of liver cirrhosis included chronic hepatitis B (79 cases), alcoholic liver disease (7 cases), autoimmune hepatitis (7 cases), chronic hepatitis C (2 cases), and other etiology (10 cases). Liver function of 32 cases was Child-Pugh A, Child-Pugh B 57 cases, and Child-Pugh C 16 cases. All 105 liver cirrhosis patients with cirrhotic portal hypertension were successfully measured the diameter of gastroesophageal varices by CHESS ruler, and the success rate of application of CHESS ruler was 100.0% (105/105). The procedure time from the CHESS ruler into the body to the exit of the body after measurement was (3.50±2.55) min. No complications happened in all the patients during measurement. Among 105 liver cirrhosis patients with cirrhotic portal hypertension, 96 cases (91.4%) were recognized as big gastroesophageal varices by the endoscopists. Totally 93 cases (88.6%) were considered as big gastroesophageal varices by CHESS ruler. Eight cases were recognized as big gastroesophageal varices by the endoscopist, however not by the CHESS ruler; 5 cases were recognized as big gastroesophageal varices by the CHESS ruler, but not by the endoscopists; 4 cases were not recognized as big gastroesophageal varices both by the endoscopists and CHESS ruler; 88 cases were recognized as big gastroesophageal varices both by the endoscopists and CHESS ruler. The missed diagnostic rate of big gastroesophageal varices by the endoscopists experience was 5.4% (5/93), and the Kappa value of consistency coefficient between the measurement by the CHESS ruler and the interpretation by endoscopists experience was 0.31 (95% confidence interval 0.03 to 0.60). The overall Kappa value of consistency coefficient by 6 endoscopists measured by CHESS ruler in big gastroesophageal varices diagnosis was 0.77 (95% confidence interval 0.61 to 0.93).Conclusion:As an objective measurement tool, CHESS ruler can make up for the deficiency of subjective judgment by endoscopists, accurately measure the diameter of gastroesophageal varices, and is highly feasible and safe.