• Completely resected pathological stage IB-IIIA NSCLC with ALK-fusion positive (confirmed by FISH, IHC or NGS).

• Males or females aged ≥18 years, ≤75 years.

• ECOG performance status 0-2.

• Completely recovered from surgery or standard postoperative chemotherapy before receiving adjuvant ensatinib treatment. (When starting the study treatment, the patient must have recovered from all toxicities greater than CTCAE Grade 1 caused by the previous treatment, except for hair loss and Grade 2 neuropathy related to previous platinum-based treatments).

• Clinical examinations before treatment report no signs of disease recurrance.

• With enough tumor histology specimens (non-cytology) for molecular marker analysis.

• hemoglobin concentration ≥ 100 g/L (permit to maintain hematologic criteria by blood transfusion); absolute neutrophil count (ANC) ≥1.5×10\^9/L; platelet count ≥100×10\^9/L.

• Liver Function: TBil ≤2xULN; ALT and AST ≤2.5xULN;

• Renal Function: Cr ≤1.5xULN, and Ccr ≥60ml/min;

• Signed inform consent form by patient or his/her legal representative.

• Comply with study protocol and procedure, and be able to take oral medication.

• Female patients of childbearing potential must have a negative urine pregnancy test within 7 days before study treatment.

• Eligible patients of reproductive potential (both sexes) must agree to use a reliable method of birth control before enrollment, during the study period and for at least 8 weeks after their last dose of study therapy.