There are differences in the normal body temperature of different groups of people. Generally, children aged 0-2 years old are considered to have fever if they exceed 38℃, 3-10 years old exceed 37.8℃, and 11-65 years old exceed 37.5℃. The ear thermometer belongs to a kind of non-contact telemetric thermometer, which utilizes the infrared spectrum emitted by detecting the tympanic membrane to determine the body temperature. Normal body temperature ranges vary somewhat among different age groups, so the use of an ear thermometer to measure body temperature needs to be customized for each individual. The normal body temperature of children aged 0-2 years is 36.4-38℃, that of children aged 3-10 years is 36.1-37.8℃, that of children aged 11-65 years is 35.9-37.6℃, and that of people aged 65 years or above is 35.8-37.5℃. Therefore when using an ear thermometer for temperature measurement, a targeted assessment is needed. Meanwhile, due to the design of the ear thermometer itself, there is an allowable error, usually ±0.2℃ in the range of 36-39℃, and ±0.3℃ when higher than 39℃ and lower than 36℃. Incorrect use of the ear thermometer will also bring additional errors, which will cause some impact on the results of the determination of fever.