Objective: To explore the significance of a DNA quantitative analysis of lung cancer cells with different pathological types taken from bronchial brush specimens and its relationship with the clinicopathological features. Methods: 903 bronchial brush cytological specimens taken in the Cytology Department of the Fourth Hospital of Hebei Medical University were collected from March 2017 to December 2019 and divided into three groups: the squamous carcinoma (SC) group, the adenocarcinoma (AC) group, and the small-cell carcinoma (SCC) group. The maximum DNA index (DI) value, the percentage of cells with a DI larger than 2.5, the mean DI, and the peaks of the aneuploid cells of the three groups were compared. A single factor analysis was used to analyze the relationship between the DNA content, aneuploidy, and the clinicopathological features of the patients who had surgery. Results: The peaks of the aneuploid cells in the SC group, the AC group, and the SCC group had no significant differences (P=0.57). The maximum DI, the percentage of cells with a DI larger than 2.5, and the mean DI of the three groups showed statistically significant differences (P 0.001). The clinicopathological features of the AC patients and the SC patients, such as gender, age, tumor type, the maximum tumor diameter, clinical stage, vascular invasion, nerve invasion, pleural invasion, tracheal spread, and lymph node metastasis were not independent factors that influence the DNA content and have no statistical significance (P 0.05). Conclusion: The reason why the DNA content of small-cell lung cancer is lower than SC and AC remains to be further studied.