Objective：To study the clinical effects of dental floss traction assisted submucosal dissection and IT knife assisted disposable mucosal dissection knife in the treatment of early gastric horn cancer and precancerous lesions. Methods：One hundred and forty-six patients with early gastric horn cancer and precancerous lesions admitted from December 2015 to August 2023 were included as study subjects. They were divided into two groups according to the treatment plan：dental floss traction group（n=73）and IT knife group（n=73）. The time of operation and lesion dissection，muscularis injury，surgical effect，and postoperative complications in the two groups were evaluated and compared. Results：The number of muscularis injury and the use of hemostatic clips were significantly reduced in the dental floss traction group compared to the IT knife group（P ＜ 0.05）. There was no significant difference in the whole lesion resection rate，R0 resection rate，curative resection rate，margin involvement rate，and perioperative complication rate （postoperative bleeding and perforation）between the two groups（P ＞ 0.05）. Univariate analysis showed that floss traction - assisted submucosal dissection with disposable mucosal dissection knife was effective in reducing muscularis injury（OR=0.37，95%CI：0.18- 0.74，P=0.006）. Conclusion：The use of dental floss assisted endoscopic submucosal dissection for early gastric horn cancer and precancerous lesions is particularly effective. It can significantly reduce the damage to the muscularis propria and ensure the safety and effectiveness of the procedure.