As we all know, childhood asthma is one of the most common chronic allergic diseases of the airways in the world today, and the spring and autumn seasons are good times for asthma. In recent years, due to ecological changes and air pollution, the incidence of asthma has been on the rise globally, especially in children, and its prevalence and mortality rates have also increased in developed countries such as the United States, the United Kingdom, Australia, and New Zealand. In China, the incidence of childhood asthma has doubled compared with the past, and now it has reached 0.5%-2%, with individual areas as high as 5%. Therefore, asthma in children has become a serious public health problem and is deeply troubling, causing great concern in countries around the world. There are many causes of asthma, among which passive smoking induces recurrent asthma attacks in children and aggravates the disease, which needs to be taken very seriously by society, especially by parents. Indoor smoking can produce 3800 compounds. It has been found that about 38% of infants whose mothers smoke are hospitalized with pneumonia within 1 year, and the hospitalization rate is directly proportional to the amount of smoking by the mother. Because infants respiratory rate and metabolism is faster than adults, passive smoking inhaled more harmful substances than adults, the same concentration of indoor smoke by weight, infants inhaled more smoke than adults. Passive smoking can also cause acute pharyngitis, bronchitis, pneumonia, and otitis media in infants. Smoking also reduces the activity of a1-antitrypsin and other proteases, thus weakening the body’s ability to inhibit room dust allergen proteins and increasing the body’s sensitivity to dust allergen proteins; heavy smoking can also inhibit T-cell function, reduce the activity of killer cells, and affect the efficacy of inhaled hormones in asthma patients. In addition, smoking can aggravate atmospheric pollution, and atmospheric O2, CO2, SO2, NO2 also have a great impact on the body of children with asthma, which can directly damage the airway mucosa and cause airway hyperreactivity, once encountered with environmental plants, pollen and indoor dust mites, cockroaches, animal fur, etc. can trigger an asthma attack or aggravate. Secondly, children with asthma who have airway hyperreactivity may also develop allergies to sulfites and spices in food due to the exposed nerve fiber endings during airway inflammation, which can trigger wheezing. In conclusion, parents of children with asthma need to carefully consider the effects of smoking on their children.