What's the main factor judged in google America?

[Victoria Monica]

I have a website and at first it run well. But lately when I SEO it (I had to say I didn'nt use any cheat methods), it's rank was highly behind in google US while rank good in google China. what's the problem?
Could someone tell me what's the probable reasons?
Thank you

[cls_wired]

The main factor is attractiveness of site-content for users from this country. Google check the behavior of users on your site and rank it in accordance with that info.

[tedster]

Hello Victoria, and welcome to the forums.

To rank well on google.com's US SERPs, you also want to look at the country where the website is hosted, and especially the domain's TLD. A country code TLD will have a much harder challenge.

There are a number of good discussions about "Geo-Targeted Search" in the Hot Topics area [webmasterworld.com], which is always pinned to the top of this forum's index page.