The main effects of male smoking on pregnancy preparation are that it may affect the quality of sperm, and it may lead to second-hand smoke that affects the quality of the eggs. If a man smokes during pregnancy preparation, it may have an effect on the sperm and eggs, which in turn affects the pregnancy process, and may lead to infertility, or miscarriage, fetal malformations, and may also lead to the development of the fetus’s intelligence or other functions, and the incidence of low birth weight babies will also increase. During the preparatory period, both men and women are to avoid exposure to all kinds of toxic and harmful factors, quit smoking and drinking, and take folic acid supplements at least three months in advance. Women should do a good job of pre-pregnancy examination, in order to facilitate eugenics.