Afatinib resistance time is between six months to one and a half years, which is determined by the condition and physical fitness. Afatinib is a potent, irreversible dual inhibitor, mainly used for non-small cell lung cancer EGFR gene mutation treatment, clinically most patients will appear drug resistance in half a year to one and a half years of medication, but the body type, treatment program and different medical conditions are different, the time of drug resistance will vary to a certain extent, and there is no definite time. After the emergence of drug resistance of afatinib, genetic testing can be carried out, according to the results of the choice of other targeted drug therapy, such as the emergence of T790M, L858R and exon 19 deletion, can be used instead of ositinib. Drugs need to be used under the guidance of a doctor, and if there is any discomfort during the use of drugs, consult a doctor in time to avoid delaying the condition.