Inclusion Criteria:
* 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.
Exclusion Criteria:
* Having targeted medication therapy (including tyrosine kinase inhibitor or monoclonal antibody) and experimental therapy for NSCLC in the past.
* Having local radiotherapy of NSCLC.
* Known allergy to Ensatinib or any of the ingredients in this product.
* Previously suffering from interstitial lung disease, drug-induced interstitial disease, radiation pneumonia that requires hormone therapy, or any clinically evidenced active interstitial lung disease; CT scan at baseline revealed the presence of idiopathic pulmonary fibrosis.
* Any unstable systemic disease, including: active infection, uncontrolled high blood pressure, unstable angina pectoris, angina pectoris that started within the last 3 months, congestive heart failure (≥ New York Heart Association \[NYHA\] II Grade), myocardial infarction (6 months before enrollment), severe arrhythmia requiring medical treatment; liver, kidney or metabolic diseases.
* Women who are pregnant or breastfeeding.
* Having history of neurological or psychiatric disorders, including epilepsy or dementia.
* Other conditions investigators evaluate that patient is not eligible to this study.
