Objective To explore the incidence of newly diagnosed malignant tumors and its association with all-cause death in the patients with coronary artery disease (CAD) to provide evidence for optimizing their comprehensive clinical management strategies. Methods According to the inclusion and exclusion criteria, a total of 4625 CAD patients were randomly selected using SPSS 25.0 from those who were admitted to the Department of Cardiology of the First Medical Center of Chinses PLA General Hospital from January 1,2011 to December 31,2015, and underwent coronary artery angiography for the first time. The patients′ baseline data were collected, and they were followed up after discharge for information about the newly diagnosed tumor and survival. They were divided into survival group (n=3385) and death group (n=335) based on outcome over the follow-up period. Cox regression analysis was used to determine the association between the newly diagnosed tumor and all-cause death in CAD patients. SPSS 25.0 was used for statistical analysis. Data comparison between two groups was performed using t-test, Nonparametric test or χ² test depending on data type. Results Among the 4625 patients included, 3720 (80.4%) were followed up with a median follow-up time of 9(8,10) years. Among them, 150 patients (4.0%) developed malignant tumors, and 335 (9.0%) died. Among those who died, 40 (11.9%) were diagnosed with malignant tumors; among those who survived, 110 (3.2%) were diagnosed with malignant tumors.There was a significant difference in the incidence ofnew tumors between two groups (P<0.001). There were statistically significant differences in age ≤65 years, body mass index≥24 kg/m², stenosis degree of left main, left anterior descending, left circumflex branch and right coronary artery, and Gensini score (>20 points) between the death group and the survival group (P<0.05). The differences were statistically significant in the patients with hypertension, hyperlipidemia, renal insufficiency, bronchitis/emphysema ratio (P<0.05). There were statistically significant differences in hemoglobin level, neutrophil-lymphocyte ratio, triglyceride, prothrombin activity, plasma fibrinogen, international normalized ratio, urea nitrogen, creatinine, alanine aminotransferase, left ventricular ejection fraction, troponin T and brain natriuretic peptide between the two groups (P<0.05). The Log-rank test showed that CAD patients with a tumor had significantly lower cumulative survival rate than those without (P<0.001) over the follow-up period. Multivariate Cox regression analysis showed that newly diagnosed tumors increased the risk of all-cause death for CAD patients by 3.815 times (95%CI 2.362-6.164; P<0.001). Conclusion The incidence of tumors in deceased coronary heart disease patients is significantly higher than that in surviving coronary heart disease patients. Newly diagnosed malignant tumors significantly affect the prognosis of long-term survival in the CAD patients.