Objective:To evaluate the clinical efficacy and toxicity of pemetrexed combined with platinum as first-line treatment of advanced non-small cell lung cancer(NSCLC) with asymptomatic brain metastasis. Methods:A total of thirty chemotherapy-naive NSCLC patients with asymptomatic brain metastasis were enrolled in this study,and all of these patients had been confirmed with NSCLC by pathology or cytology. Patients received pemetrexed 500 mg/m2 on day 1,and cisplatin 25 mg/m2 for three days or carboplatin(AUC=5) on day 1. Every 3 weeks as one cycle. All patients who received 1 or more cycles could be evaluated. Results:Thirty patients were evaluable for objective response. Local cerebral response assessment showed that 10 patients(33.3%)got a partial response(PR),14(46.7%) had a stable disease(SD) and 6(20%) had a progressive disease(PD). The response rate was 33.3%,the disease control rate was 80%,and the median time to progression was 6.5 months. Overall lesion assessment presented that 7(23.3%),14(46.7%)and 9(30%) patients got PR,SD and PD,respectively. The response rate was 23.3%,the disease control rate was 70%,and the progression-free survival was 5 months. The common adverse effects were hematological toxicity and gastrointestinal response,and the toxic reactions could be well controlled with relative therapy. Conclusion:Pemetrexed combined with platinum regimen is effective and well tolerable for advanced NSCLC with asymptomatic brain metastases.