Lead and its compounds are toxic. In addition to metallic lead, there are many lead compounds, such as lead monoxide, lead tetraoxide, lead dioxide, etc. Since the neurotoxic effect of lead can often cause damage to children's intellectual development before obvious clinical manifestations appear, the study and prevention of the harm of lead to children is undoubtedly of great practical significance in today's society where survival and development depend on intellectual competition. Therefore, research on lead is becoming one of the hot topics in the field of pediatrics. Lead is a heavy metal element with neurotoxicity. It has no physiological effect in the human body and its ideal blood concentration is zero. However, due to the ubiquitous presence of lead in the environment, most individuals have a certain amount of lead to a greater or lesser extent. When the amount of lead in the body exceeds a certain level, it will cause health hazards. Before the 1960s, the understanding of lead poisoning in children remained at the clinical stage, and the diagnosis of lead poisoning was considered only when convulsions, seizures and coma occurred. Subsequent studies have found that the damage of lead poisoning to the body already exists before the onset of clinical symptoms, thus proposing the concept of subclinical lead poisoning, which has been used to this day. Therefore, unlike the traditional meaning of poisoning, lead poisoning in children does not mean poisoning in the clinical sense like organophosphorus poisoning and nitrite poisoning, but means that the accumulation of lead in the body (i.e., lead load) is already at a dangerous level that is harmful to health. In the 1960s, children's blood lead levels were considered safe below 2.88μmol/L (60μg/dl). As research deepened, the blood lead levels that were previously considered normal were successively proven to be harmful. It was not until the 1980s that research suggested that blood lead levels of around 0.48μmol/L (10μg/dl) were not enough to produce specific clinical manifestations, but could have an adverse effect on children's intellectual development, physical growth, learning ability, and hearing. Based on a large number of scientific studies, in 1991, the Center for Disease Control (CDC) of the United States formulated the diagnostic criteria for lead poisoning in children as blood lead levels greater than or equal to 0.48μmol/L (10μg/dl), regardless of whether there are corresponding clinical manifestations and other blood biochemical changes.