Provided is an air interface security method. In the process of protocol transmission, the method executes: 1) a short-range coupling device sending a security parameter request message to a short-range card; 2) after receiving the security parameter request message, the short-range card conduct security parameter feedback on the short-range coupling device; and 3) the short-range coupling device and the short-range card establish a security link according to a security parameter. Provided are a short-range coupling device, a short-range card, etc. for achieving the method. By introducing a security mechanism, the present invention provides a security protection capability for an air interface, can provide identity authentication for a short-range coupling device and a short-range card to ensure the validity and authenticity of the identities of both sides in the communications, and at the same time, will not bring additional hardware overhead to the short-range coupling device and the short-range card.