Objective To evaluate the cognitive level of malignant tumor-related knowledge of surface warship soldiers, and to understand their attitude and behavior towards the prevention and control of malignant tumors. Methods A total of 1 600 surface warship soldiers were selected by using cross-sectional cluster sampling method. A self-made questionnaire was used to investigate the demographic data and malignant tumor prevention and control knowledge (malignant tumor-related prevention knowledge, basic malignant tumor knowledge, understanding of malignant tumor-related health literacy and demand for malignant tumor-related knowledge). Military doctors conducted a written questionnaire survey in a face-to-face manner. Results A total of 1 509 (94.3%) valid questionnaires were obtained. The total scores of the 3 cognitive dimensions of malignant tumor-related prevention knowledge, basic malignant tumor knowledge and understanding of malignant tumor-related health literacy was 12.00 (10.00, 14.00), while the scores of the 3 cognitive dimensions were 5.00 (4.00, 7.00), 3.00 (3.00, 4.00) and 3.00 (2.00, 4.00), respectively. The total scores of each age group and educational background showed a gradual increasing trend (P<0.001). The total score of females was higher than that of males (P<0.001). There was a significant difference in the total scores between those with different marital statuses (P<0.001):married people scored the highest and widowed people scored the lowest. Conclusion The awareness of malignant tumor prevention is low. Gender, age, education level and marital status are related to malignant tumor-related prevention knowledge and health literacy.