This is a randomized, controlled, open-label, phase III trials. The main purpose of this study is to evaluate the effectiveness and safety of tumor treating felds (TTF) combined with stereotactic radiosurgery (SRS) in the treatment of brain metastases from non-small cell lung cancer (NSCLC) .

Inclusion Criteria:

1. The age of the subject was between 18 and 75 years old (inclusive), regardless of gender;
2. The predicted survival time was ≥3 months;
3. Newly diagnosed with NSCLC brain metastasis;
4. MRI imaging showed 1-10 unresectable brain metastases;
5. Karnofsky performance status (KPS) score ≥70;
6. Able to operate the TTF independently or with the help of a caregiver;
7. Subjects of childbearing potential had to agree to use effective contraception for the duration of the trial;
8. Voluntarily signed the informed consent form.

Exclusion Criteria:

1. Positive driver genes;

2. Recurrent brain metastasis of NSCLC;

3. Suffering from severe cerebral edema;

4. Leptomeningeal metastases;

5. Participants had to meet certain criteria for bone marrow, liver and kidney function before enrollment, and were not eligible if they had any of the following:

   1. platelet count < 100×103/μL;
   2. absolute neutrophil count < 1.5×103/μL;

   d. AST or ALT exceeding 2.5 times the upper limit of normal; c.Total bilirubin more than 1.5 times the upper limit of the normal range; d.Severe renal impairment (serum creatinine >1.7 mg/dL, or >150 μmol/L);

6. There were infection, ulcer and unhealed wound in the skin where the electrode was applied；

7. Patients allergic to conductive hydrogels or medical adhesives;

8. Those who are pregnant or preparing to become pregnant or who are breastfeeding;

9. Patients with poor compliance, as judged by the investigator, or other factors considered by the investigator to be not suitable for the study.