Hepatitis B virus (HBV) is a blood-borne disease, mainly transmitted via blood (e.g. unsafe injections, etc.), mother-to-child and sexual contact. Due to the implementation of strict HBsAg screening for blood donors, HBV infection caused by blood transfusion or blood products has been less frequent; transmission through broken skin and mucous membranes is mainly due to the use of medical devices that are not strictly sterilized, invasive diagnostic and surgical operations, unsafe injections, especially drug injection; other things such as pedicure, tattoo, earring piercing, accidental exposure of medical personnel at work, sharing razors and toothbrushes, etc. can also be transmitted. Other factors such as foot trimming, tattooing, earring piercing, accidental exposure of medical personnel at work, sharing razors and toothbrushes, etc. can also be transmitted. Mother-to-child transmission occurs mainly during the perinatal (labor) period, mostly from contact with the blood and body fluids of HBV-positive mothers during delivery, but with the use of hepatitis B vaccine combined with hepatitis B immunoglobulin, mother-to-child transmission has been greatly reduced. The risk of HBV infection increases with unprotected sexual contact with HBV-positive people, especially those with multiple sexual partners. Epidemiological and experimental studies have not found that HBV can be transmitted by blood-sucking insects (mosquitoes, bedbugs, etc.).