Late syphilis is less contagious than early syphilis. Syphilis is a chronic, systemic sexually transmitted disease caused by infection with the syphilis spirochete. Clinically, it can be divided into three phases, of which the first and second phases are early syphilis and the third phase is late syphilis. Late syphilis is generally untreated or incomplete treatment of early syphilis, after more than 2 years of development, become late syphilis. Early syphilis patients usually have more syphilis spirochetes in their bodies and are more contagious. 2 years later, when they enter late syphilis, the number of spirochetes in their bodies decreases, so late syphilis is less contagious than early syphilis, and patients who have been infected for more than 4 years are not basically contagious. Late syphilis can cause damage to the patient’s skin, internal organs and other organs, seriously threatening the patient’s life. Therefore, it is recommended that patients suffering from syphilis should undergo timely and effective treatment to prevent the disease from progressing to an advanced stage.