Objective: To investigate the diagnosis, treatment and prognosis of ovarian yolk sac tumor (OYST). Methods: The clinicopathological data and follow-up data of 12 patients with OYST admitted to the Affiliated Hospital of Qingdao University from January 2013 to December 2020 were retrospectively analyzed, and the diagnosis, treatment and prognosis of OYST patients were summarized. Results: (1) The age of 12 patients with OYST ranged from 11 to 37 years, with a median age of 20 years. At the first visit, all 12 patients had pelvic masses. Reasons for seeing a doctor: 6 cases of abdominal distension and abdominal pain, 4 cases of mass in the lower abdomen, 1 case of vaginal bleeding, and 1 case of appendicitis. International Federation of Obstetrics and Gynecology (FIGO) 2014 staging: 4 cases in stage Ⅰa, 2 cases in stage Ⅰc, 1 case in stage Ⅱc, 4 cases in stage Ⅲc, and 1 case in stage Ⅳb. (2) All 12 patients were examined by color Doppler ultrasound before operation, among which 10 cases showed unilateral adnexal masses and 2 cases bilateral adnexal masses. The median maximum diameter of tumor was 16.5 cm (range: 6.0-28.0 cm). The preoperative levels of alpha fetoprotein (AFP) in 12 patients (all >1 210 μg/L) were significantly higher than normal (<25 μg/L). Among the 11 patients with cancer antigen 125 (CA125) detection results, 9 patients showed elevated serum CA125 levels. (3) Among the 12 patients, 8 young infertile patients who needed to preserve their reproductive function underwent appendectomy, 3 infertile patients underwent staged surgery for ovarian malignant germ cell tumor, and only one bilateral lesion and infertile patient underwent unsatisfactory staged surgery for ovarian malignant germ cell tumor. Of the 12 patients, 11 patients were given combined chemotherapy regimen of bleomycin, cisplatin, and etoposide (BEP) after operation. One patient without chemotherapy developed metastasis 3 months after operation, and was given BEP chemotherapy, and her condition was controlled. (4) The deadline for follow-up was December 31st, 2022, and the median follow-up time was 60 months (range: 25-115 months). All the 12 patients survived without tumor during the follow-up period, and the median disease-free survival time was 84.5 months (range: 25-115 months). Conclusions: OYST mostly occurs in children and young women. Color Doppler ultrasound examination and serum AFP and CA125 detection have diagnostic value for OYST. Surgical treatment after diagnosis of OYST includes surgery to preserve reproductive function and timely and standardized chemotherapy after operation. The prognosis of patients is good regardless of stage.