Hepatitis B is a viral disease mainly transmitted by blood, the occurrence of infectious diseases through the source of infection; transmission route; susceptible people, the three major elements. Do mosquitoes transmit hepatitis B? Mosquitoes can transmit many viral diseases, such as encephalitis B, dengue fever, and sika virus, etc. The 2015 guidelines for the prevention and treatment of chronic hepatitis B in China contain a paragraph describing that epidemiological and experimental studies have not found that HBV can be transmitted by blood-sucking insects (mosquitoes, bedbugs, etc.). This paragraph comes from the World Health Organization on the prevention and treatment of hepatitis B virus. In fact, there have been many studies on the issue of whether mosquitoes transmit hepatitis B. It is also the final comprehensive conclusion of many studies. There are also many scientific conclusions that mosquitoes transmit hepatitis B. For example, our 1995 in the English version of the Chinese Medical Journal there is such a study: three mosquitoes were artificially eaten infected with hepatitis B virus (HBV) of human blood. When the blood in the stomach was completely digested, the mosquitoes were used to bite experimental monkeys. One month after the bite, venous blood samples were taken from the monkeys to test for serum HBsAg, HBeAg, anti-HBs and anti-HBc. 9 of the 29 test monkeys were infected with HBV. acute inflammatory changes were found in 16 test monkey liver biopsies. In hepatocytes, HBsAg and HBcAg were detected by immunohistochemical double-labeling, and in situ hybridization in monkey liver sections tested positive for HBV-DNA. These results provide evidence for the possibility of hepatitis B virus transmission through mosquitoes and suggest its epidemiological significance in mosquito-breeding areas. It is also very interesting to look at another study that also supports the idea that mosquito transmission of hepatitis B virus, especially occurring in those who have not eaten enough in one person have then gone on to bite another person, is possible. Another in-person study, from India, prospectively studied the frequency of malaria and acute hepatitis B over a three-year period to understand the seasonal variation in the frequency of both diseases and (b) any correlation between the seasonal frequency of the two diseases. The study was conducted in a busy general hospital Gujrat and Institute of Medical Research. The frequency of malaria and acute hepatitis B was monitored monthly, prospectively for three years. Malaria was clearly a seasonal disease, but no clear peaks of acute hepatitis B were recorded. The correlation or association between the frequency of malaria and acute hepatitis B does not prove that mosquito bites may lead to HBV transmission. Today, as a matter of scientific interest, I have systematically reviewed the literature on “mosquito-borne hepatitis B.” It is interesting to note that this issue has been of interest since the discovery of HBsAg in the 1970s, and the earlier the studies, the more supportive the conclusion that mosquitoes transmit hepatitis B. Of course, the more recent studies are more scientific, and the conclusion is that it is not transmitted. In short, the current authoritative assertion that mosquitoes do not spread hepatitis B. The reasons are as follows: 1, the mosquito itself has the enzyme to digest hepatitis B virus, can be hepatitis B virus loss of infectious; 2, hepatitis B virus difficult to replicate in the mosquito; 3, mosquitoes suck too little blood, not enough to spread hepatitis B virus; 4, most healthy people already have hepatitis B virus antibodies, can be enough to block hepatitis B virus infection.