The main ways of gray nail infection are direct contact transmission and indirect contact transmission. 1. Direct contact: gray nails are also known as onychomycosis, which is mainly due to fungal infections such as Trichophyton rubrum and Candida. The common way of transmission of gray nails is through direct contact, such as normal people shaking hands with patients, patients who don’t have gray nails but suffer from athlete’s foot, and picking their feet with their hands. 2. Indirect contact transmission: indirect contact transmission is also known as vector transmission, such as gray nail patients use nail clippers without cleaning, the normal population with its nail clippers, or patients contact bus handrails, elevator handrails, the normal population and then contact, etc., may cause gray nail infection. At the same time, wearing shoes worn by the patient and touching the patient’s socks may also cause gray nail infection. The main way of transmission of gray nails is contact transmission, it is recommended that normal people use the tools used by patients with gray nails to disinfect them in time before use, and try to avoid direct physical contact with the patient to avoid infection.