Objective To reinforce the knowledge of MRI of cystic brain metastasis of lung cancer and improve the diagnostic level. Methods Collecting totally 180 cases data which have been confirmed by clinic and pathology as brain metastasis of lung cancer from January of 2015 to August of 2016 in our hospital, review and analyze their MRI indication, routine scan of T2-Tra, Flair Tra, T1-Sag for 180 cases, enhancement scan of Gd-DTPA contrast agent T1-Tra, T1-Cor, T1-Sag for 110 cases. Results Result 63 cases are diagnosed as cerebral hemisphere metastases, 14 cases as cerebellar hemisphere metastases, 81 cases are both cerebral hemisphere and cerebellar hemisphere metastases, 22 cases whole brain (both sides cerebral hemisphere cerebellar, hemispher and brainstem) metastases, 2 cases whole brainmetastases with meninx metastases among hem. Brain swelling was found around the lesion for 159 cases, cystoid necrosis was found on 84 cases, hemorrhage was found on 49 cases. Conclusion MRI plain and enhancementscan has a high diagnostic value for brain metastasis of lung cancer; it can accuratelyevaluate the location, quantity, shape, size, edema range, tumor extraction extent and compression situation of surrounding brain tissue on patients’ lesions. It can provide strong basis for the clinicians and patientswhile choosing the treatment plan.