Hi Zahid Ali,
Thank you for using our services.
Do you mean that you want to prevent the menu control from expanding and showing children pages? If this is the case go to your site menu control on the page or template click Edit go to Behavior section and modify the LastExpandLevel property to 1. From this property you can set how many levels to expand.By default it is 0 and means that it will expand all levels.
the Telerik team