A method for subscribing for presence information, wherein: a delegated watcher client or an application server sends a subscription message of a watcher client to a presence server; when determining that the subscription message is a delegated subscription, the presence server processes the message according to delegation authorization rules; when determining that the subscription message is a non-delegated subscription, the presence server processes the message in non-delegated subscription mode; and the presence server saves the subscription relation obtained by processing the message. The present invention further provides a system for subscribing for presence information and a presence server. By employing the present invention, the subscription mode of the presence information may be made more flexible.