How to remove standard button from custom object list view page in Salesforce?

Hi Upendra,

Go into the custom object's definition and scroll down to the Search layouts section, and look at the <SObject> List View for your custom object.  The 4th column from the left ('Buttons Displayed') shows you which buttons are currently displayed when you are on the list view.

Clicking Edit next to the List View will bring you to the selection screen where you can add/remove the Standard Buttons as well as any custom buttons that you may have created.

I hope this helps you out!