A breast cyst is common in premenopausal women (61.5%) in comparision with the menopause population (39.4%) and the most common age is 35 to 50. The treatment of breast cyst using a microwave with a lot of advantages should be a considered method. This study aims to evaluate the early result of breast cyst treatment with microwave in ultrasound guidance in breast unit of Cho Ray hospital. The authors prospectively reviewed patients who underwent breast cyst treatment using microwave ablation at the Unit of Breast, Cho Ray Hospital from August 2018 to March 2020. Results showed that 58 patients are reviewed. The average age is 45.3. The proportion of simple breast cyst, complicated breast cyst and complex breast cyst are 80.0, 16.93, and 3.07%, prospectively. The average diameter of ablated cysts is 23.86 mm. All of the patients have complete respondence after treatment, the decrease in size ratio has reach more than 90% after 6 months. No complication is recorded in treatment process. There is one case, with calcification of cyst wall, do not respond with microwave ablation. Microwave ablation procedure is the promising method for symtom breast cyst with high rate of success and low rate of complication. Breast cyst with calcificated wall should have careful assessment before the procedure.