...1) Aged 18 to 70 years; 2) Histologically or cytologically confirmed non-small cell lung cancer with stage IV disease; 3) HER2 exon 20 insertion mutations, primary HER2 missense mutations or primary HER2 amplification (HER2 copy number detected by NGS testing >= 3.62 or HER2 FISH+) confirmed by tumor tissue or plasma, pleural effusion, cerebrospinal fluid or other specimens; 4) Pretreated with first-line chemotherapy or ErbB-TKI targeted therapy and had experienced disease progression; 5) At least one radiographically measurable lesion exists; 6) Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1; 7) Life expectancy of more than 12 week; 8) Left ventricular ejection fraction (LVEF) >= 50 percent (%) by echocardiogram (ECHO); 9) Adequate hepatic, renal, and hematologic functions are required including following parameters; a. ANC>= 1.5 x 10^9/L (1,500/mm3) b. Platelet count: >= 100 x 10^9/L (100,000/mm3) c. Hemoglobin >= 80 g/L (8 g/dL) d. SCr<= 1.5 x upper limit of normal (ULN) or creatine clearance rate >= 60 mL/min e. Total bilirubin <= 1.5 x ULN f. ALT and AST <= 2 x ULN or ALT and AST <= 5 x ULN for patients with liver metastasis g. INR <= 1.5 x UNL, PT and APTT <= 1.5 x UNL; h. Urine protein < 2+and if urine protein >= 2+, 24-hour urine protein quantitation shows that protein must be <= 1g; 10) Provide written, informed consent to participate in the study and follow the study procedures....