Objective: To explore the application effect of an artificial intelligence (AI)-assisted diagnostic system in the clinical diagnosis and treatment of digestive system tumors (including gastric cancer, colorectal cancer, liver cancer, etc.), providing evidence-based support for improving the efficiency and accuracy of diagnosis and treatment of digestive system tumors. Methods: A total of 200 patients with digestive system tumors admitted to our hospital from January 2022 to December 2024 were selected and divided into an observation group (n = 100, receiving AI-assisted diagnosis combined with conventional diagnosis and treatment) and a control group (n = 100, receiving conventional diagnosis and treatment) according to the random number table method. The differences in diagnostic and treatment indicators between the two groups were compared. Results: The diagnostic time in the observation group was 18.25 ± 3.68 minutes, significantly shorter than that in the control group (35.72 ± 5.14 minutes) (t = 25.36, P < 0.001). The missed diagnosis rate and misdiagnosis rate in the observation group were 2.00% (2/100) and 1.00% (1/100), respectively, significantly lower than those in the control group [8.00% (8/100) and 7.00% (7/100), respectively] (χ² = 4.01, 5.03, both P < 0.05). Conclusion: The AI-assisted diagnostic system can significantly improve the diagnostic accuracy of digestive system tumors, shorten the diagnostic and treatment time, and reduce the missed diagnosis and misdiagnosis rates, demonstrating high application value in the clinical diagnosis and treatment of digestive system tumors.