Coffee contains caffeine, which has a stimulating effect on the central nervous system of the brain, and can dilate blood vessels and promote blood circulation throughout the body. Therefore, coffee consumption has a refreshing and energizing effect on the brain. With the growing group of coffee drinkers, the effect of coffee on human health and sperm production function has also received widespread attention. Data show that coffee has a greater effect on reproductive function in men than in women. The chemical nature of caffeine is an inhibitor of cyclic nucleotide phosphodiesterase. It is previously believed that caffeine increases intracellular calcium in-flow and reactive oxygen species production in sperm, activating intracellular adenylate cyclase, leading to an increase in intracellular cyclic adenosine monophosphate (cAMP) concentration, thereby enhancing sperm motility and promoting sperm capacitation. In short, it means that cAMP in sperm cells is closely related to sperm motility, and caffeine can increase the concentration of cAMP in sperm. Therefore, caffeine was once used as an in vitro sperm promoter for the optimized processing of semen during artificial insemination and in vitro fertilization treatment. However, it is now believed that coffee intake has no significant improvement on parameters such as sperm concentration and viability; on the contrary, long-term caffeine intake may also damage the integrity of sperm DNA and increase the incidence of sperm chromosome aneuploidy, leading to reduced male fertility. Men who consumed coffee for a long time had a significantly longer average time to conception for their wives compared to men who did not have a coffee habit. The body’s vegetative nervous system, which regulates internal functions, is divided into two parts: the sympathetic nervous system and the parasympathetic nervous system, both of which have opposite roles and are mutually regulated. When the body is under stress, the sympathetic nervous system plays a major role, and therefore, the sympathetic nervous system governs the daytime activities of the body. Quiet states and nighttime physiological activities are more controlled by the parasympathetic nervous system. Caffeine mainly stimulates the sympathetic nervous system in our body, which may inhibit the action of the parasympathetic nervous system to some extent. The parasympathetic nervous system is responsible for the erectile function in men, and once it is inhibited, the erectile function of men may be affected to some extent. Therefore, for men with reproductive requirements, especially the relatively low sexual function of the elderly male population, it is best to avoid drinking coffee at night to prevent reducing libido. Although rich and aromatic coffee has the benefits of being delicious, refreshing and restorative, men with fertility needs should try to avoid drinking too much. In addition to the adverse effects on fertility, excessive caffeine intake may also increase the risk of heart disease, osteoporosis, stroke and other diseases in men. Therefore, for men who are coffee lovers, they should control their daily coffee consumption appropriately; moderate amounts are beneficial, while excessive amounts are harmful.