A method and device for establishing link are provided. The method for establishing link is applied to an Ad-Hoc network includes: generating, by a first electrical device, a first part of a service set identifier according to a user's name and a network-card address; generating a second part of the service set identifier according to the first part of the service set identifier, a private key and a first algorithm; generating the service set identifier according to the first part of the service set identifier and the second part of the service set identifier; generating a link password according to the service set, the private key and a second algorithm; and establishing, by a second electrical device, a link with the first electrical device according to the service set identifier, the private key, the first algorithm and the second algorithm.