Cervical cancer, endometrial cancer and ovarian cancer are common malignant tumors in gynecology. To prevent the occurrence of cancer, we must achieve “three early stages”, namely early detection, early diagnosis and early treatment. Cervical cancer is the only cancer that can be detected early and completely cured. Regular cervical cytology and HPV screening (once a year for three years and thereafter depending on the condition) are of great importance for early detection of cervical lesions and cervical cancer. Cervical cancer can be prevented by timely treatment of cervical lesions; cervical cancer can also be completely cured by preserving physiological functions or reproductive functions if detected early. Endometrial cancer has a high incidence at the age of 58~61 years old. Long-term estrogen stimulation, heredity, hypertension, hyperglycemia and obesity and other physical factors are all causes of the disease. Patients with long-term functional uterine bleeding and postmenopausal vaginal bleeding should be aware of the occurrence of this disease. Ovarian cancer is a gynecologic malignancy that is difficult to detect early and has a high mortality rate. Internal gynecological examination, semiannual negative ultrasound and tumor marker examination are of great significance for its early detection.