Hi there, whenever I was log in gmail than our ranking top one, why do so happen that our site top one, why not any other site top one, I am very confuse. your suggestion would be appreciated.
it's because google accounts have search history, you can view it in google.com/history and once you click on a search result, google will remember it and that site will rank higher for you.
Besides you may have promoted your site (see the arrow to the right of the result) - if the arrow is green means the site has been promoted.
This is a personalized search, which allows users to customize and comment on Google search results. When logged into their personal accounts, users can move results up or down or remove them altogether.