The invention provides a method, a device and a system for analyzing a channel drainage effect in a website. The method comprises the following steps that: according to a page type, classifying an important page, and endowing each category of important pages with a corresponding logo, wherein the important page is a website page to be subjected to drainage effect analysis; according to a browsingsequence and a principle of proximity coverage, recording the logo of the important page browsed by a user, wherein the principle of proximity coverage means that the logo recorded according to the browsing sequence is updated so as to cover the log of the important page which is browsed previously with the logo of the important page which is browsed later; when a commodity is added into a shopping cart, reporting the recorded logo and order form information, and storing the reported data in a dimension table, wherein the order form information comprises user information, commodity informationand order form state information, and revising the order form information in the dimension table into order placing when the user places an order; and according to the dimension table, carrying out statistics on the drainage effect data of the important page. By use of the method, the drainage effect between pages can be accurately calculated.