This project is aim to explore non-increased-intracranial-pressure symptomatic brain metastases of NSCLC, and if the OS of secondary brain radiotherapy after recurrence with Erlotinib is better than Erlotinib with concurrent brain radiotherapy. Treatment group are treated with Erlotinib until brain tumor progression, then gave brain radiotherapy, and continued to take Erlotinib till extracranial lesions progression. Control group are Erlotinib with concurrent brain radiotherapy, and continued to take Erlotinib after radiotherapy until recurrence or termination for other reasons.

Inclusion Criteria:

1. Over the age of 18 years old;
2. Tissue or cell pathological diagnosis of NSCLC;
3. Brain CT or MR validated BM;
4. Non-increased-intracranial-pressure symptomatic BM;
5. Haven't received TKI target treatment;
6. Haven't received brain radiotherapy;
7. Patients in initial treatment should be detected EGFR mutation;
8. Expected survival more than 6 months;
9. KPS no less than 70, or KPS less than 70 caused by paralysis due to recent brain metastases;
10. Liver and kidney function requirements: SGOT/SGPT≦2.5 times of the upper limit, Total bilirubin≦1.5 times of the upper limit, serum Creatinine≦1.5 times of the upper limit;
11. Routine blood test requirements: WBC≧3.0×109/L, NE≧1.8×109/L, PLT≧90×109/L，no requirement for Hb;
12. Blood glucose requirements: within the normal range, diabetic patients are receiving treatment and their glucose was being controlled in a steady state;
13. Female patients in childbearing age: HCG (-);
14. Patients signed an inform Consent.

Exclusion Criteria:

1. Those with Erlotinib drug allergies;
2. Those with mathematical understanding of the most simple life questions, such as "walking", those difficult for doctors to communicate;
3. Those without guardians or families;
4. Those with abnormal routine blood test, liver and kidney function, and blood glucose beyond the above boundaries and difficult to correcting for more than 2 weeks;
5. Those with any unstable medical status (including active infection, uncontrolled hypertension, unstable angina, congestive heart failure, myocardial infarction (within one year before treatment initiation), and severe arrhythmia, liver, kidney or metabolic disease requiring drug therapy);
6. Those with any other disease, neurological or metabolic dysfunction, and physical examination or laboratory test results showed that the study drugs may increase the risk of treatment-related complications;
7. Pregnant women.