Advanced non-small-cell lung cancer (NSCLC) patients without epidermal growth factor receptor (EGFR) mutations show a poor prognosis. Gemcitabine combined with cisplatin chemotherapy is an effective treatment measures for EGFR mutation-negative NSCLC patients,but the prognosis remains poor. Chemotherapy combined with targeted monoclonal antibody treatment may be better treatment options in these patients. Monoclonal antibodies,such as bevacizumab,can block tumor growth in different ways. Bevacizumab blocks the ability of tumors to grow new blood vessels and spread. It is not yet known whether cisplatin and gemcitabine is more effective when given alone or with bevacizumab. This randomized trial studies how well giving cisplatin and gemcitabine alone or in combination with Bevacizumab (Avastin) works in treating patients with stage IIIB/IV non-squamous NSCLC without EGFR mutations.