At present, a considerable number of patients are taking nucleoside (acid) drugs to treat chronic hepatitis B or hepatitis B cirrhosis, but some patients are in a panic when they learn that there is a possibility of drug resistance to nucleoside (acid) drugs. In fact, if these drugs are used regularly and reasonably, the chance of drug resistance is still rare. However, drug resistance can be easily induced if the drugs are not used regularly, or if the drugs are changed or stopped at will. How can we find out if a drug is resistant? In patients with good viral control, HBV DNA testing is all that is required. If HBV DNA is not detected by high-precision testing methods, it means there is no drug resistance, but if it is detected again, we should be highly alert to the possibility of drug resistance. At this point, a drug resistance gene test is needed. Depending on the drug-resistant mutation site, there may be a decrease in sensitivity to different drugs, which is drug resistance. However, sometimes when the test is done and no drug-resistant variants are found, it is not certain that the drug is not resistant, but it has to be analyzed based on a combination of circumstances. If there is indeed an elevated viral rebound, the treatment plan needs to be adjusted in a timely manner. In order to avoid further damage to the liver and aggravate liver damage.