Hello Dhanu,
To measure the page loading time, you can measure the time taken by the Page.Wait function to work.
Here is a sample script demonstrating how to do this:
function Test()
{
var iexplore, page, startTime, loadTime;
iexplore = Sys.Process("IEXPLORE");
page = iexplore.Page("*");
page.ToUrl("http://www.automatedqa.com/");
page.Form("aspnetForm").Panel(1).Panel(0).Panel(1).Panel(0).Link(6).Click();
startTime = GetTickCount();
page.Wait();
loadTime = GetTickCount() - startTime;
Log.Message("Page load time: " + loadTime + " ms");
}