From past 2-3 days I have noticed that my site's ranking is fluctuating.sometimes it comes in first 10 results or in first page and next day it's moves on second page or third page.Some keywords which are not in ranking under 100 comes on second page and next day it's not in up to 300 results.

I am not getting the reason why it happens so rapidly.If anyone find the reason then plz let me know

The reason is because that's the nature of Google.

1) Google appears to be updating right now.

2) You're looking in the wrong area for information. Rank checking accomplishes nothing, since different Google servers can produce different information at different times.

Are you seeing referral traffic for those keywords/phrases (and for others)? If not, then you've got a problem.

Welcome to the Google Dance, you should remember she never gets tired

Maybe coz its not done updating your site ranking.
Give it time..

Yes its true ,google rankings are not correct these days

G.o.o.g.l.e is dancing

They updating PR again recently.

Thanks to all.

I know that google is updating.yesterday in morning my site was in 5 position in Google but in evening its in 4 page of google.But today its again in its 5 position.I dunt know wht's happening.U have faces this type of problem????

Don't fret as it will normalize soon enough

Just continue on with your efforts for ranking in SERP and wait out the dance..

I think you are confusing page rank with search result placment. They are different things put out by the same beast.

If you are talking about where your site comes up in an actual search, that fluxuation can be the result of other sites developing more relevant or up-to-date content. My site is sometimes in the top position on the first page of search results for a search term and at other times will be on page two for the same search term. At least in a Google search. The page rank of my site is only 1 or 2 I think. Not too worried about it.

Seems a bit odd that ranking when people are searching fluctuates quite randomly, I thought positions were fairly 'set' as such and that that sites didnt change their position much. How much does everyone value page ranking, because it can seem to vary and doesn't seems more like a tool for getting a rough estimate of teh site and how many links are going in/out.

Its all natural! It always happen in google.

Seems a bit odd that ranking when people are searching fluctuates quite randomly, I thought positions were fairly 'set' as such and that that sites didnt change their position much.

It's because Google has a lot of data centres that are rarely, if ever fully synched up.

Some have different datasets,
Some are running different algo versions

And each one is constantly fluctuating as new pages are added to one datacentre, or pages drop out of another.

it really happens. maybe when google updating.

and that is all day, every day