The invention discloses a method and a device for detecting the existence of a weak password on a website, The method comprises: entering the detection password on the Web site login page, determiningwhether a page jump occurs on the login page, wherein the detection password is the username and password used for detecting the existence of weak password on the website, once you have determined that a page jump has occurred on the login page, recording the link to the page after the jump, judging whether the link of the page after jumping is the link of the login page, if not, after clearing the first cache, revisiting the link to the page after the jump, the first cache being a cache for identifying a user generated in the process of inputting a detection password to a link of a page after recording a jump in a login page, and when it is determined that a page jumped after revisiting the link of the jump page is a login page, the detection password being determined to be a weak password of the website. The technical scheme can quickly and accurately detect the existence of weak passwords on the website.