How to receive data from php server by delphi clie

Please I need to know how to send parameters from Delphi application to php page then php will make some calculations on these parameters and return result again to Delphi?

One of straight-forward ways in REST pattern (http://en.wikipedia.org/wiki/REST) would be:

Getting JSON data from a website using Delphi
How to send/receive JSON?

1) Your Delphi client gets the page, passing all the parameters as HTTP GET or HTTP POST.

http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol#Request_methods
How are parameters sent in an HTTP POST request?
What's the simplest way to call Http GET url using Delphi?
What’s the simplest way to call Http POST url using Delphi?
Synapse Delphi HTTPS SSL GET Request

using any library you wish. Some choices (not complete list) include:

WinInet (Windows system library) http://msdn.microsoft.com
Internet Component Suite http://OverByte.be
Internet Direct http://indyproject.org
Synapse http://synapse.ararat.cz
URL Grabber from JediVCL http://jVCL.sf.net
parts of mORMot framework http://synopse.info

et cetera

2) your PHP server gets those parameters and generates JSON page with the results

How to generate json using php? - and all the links to manuals and tutorials there

3) your Delphi client getting the page via HTTP, then parses JSON and works with the resulting variables

Some libraries to parse JSON are

SuperObject Delphi / SuperObject - Accessing Subnodes and SuperObject - Extract All and other superobject questions
parts of mORMot framework http://synopse.info
Using DB Express in Delphi Enterprise https://stackoverflow.com/search?q=delphi+TJSONObject

4) do with the received data what you want to do