Abstract： Objective:To explore the effects of hyperbaric oxygen（HBO）combined with intensity-modulated radiation therapy（IMRT）on tumor markers and myocardial zymogram in patients with lung cancer，and analyze its effect on the prognosis.Methods:A total of 102 lung cancer patients admitted to Linyi Central Hospital from February 2019 to February 2021 were selected as research subjects. They were randomly divided into control group and observation group using a random number table，with 51 cases in each group. The control group was treated with IMRT，and the observation group was given hyperbaric oxygen therapy on the basis of the treatment in the control group. Patients in both groups had been followed up for 6 to 24 months. The levels of tumor markers［serum carcinoembryonic antigen（CEA），cytokeratin 19 fragment antigen 21-1（CY-FRA21-1），and carbohydrate antigen 19-9（CA19-9）］，myocardial zymogram indicators［creatine kinase（CK），creatine kinase isoenzyme（CK-MB），lactate dehydrogenase（LDH）］and their prognosis were compared before and after treatment in the two groups.Results:After six weeks of treatment，the levels of tumor markers and myocardial zymogram indicators in both groups were lower than those before treatment，and the decreases in the observation group were more significant than those in the control group（ P<0.05）. After 24 months of treatment，the survival rate of the observation group was 54.90%（28/51），and that of the control group was 45.10%（23/51），there was no statistically significant difference between the two groups（ χ2=0.980， P=0.322）. Conclusion:For patients with advanced lung cancer，hyperbaric oxygen combined with IMRT can inhibit the expression of tumor markers，reduce myocardial damage，and to a certain extent，improve the survival rate of patients.