The bulletin, to start on 10 May and hosted by Huw Edwards, a Welshman, will have separate headlines for Scotland, Northern Ireland and Wales at the beginning of the programme, with regional "op-outs" at 6.15pm.
The changes are intended to deal with news from the Scottish Parliament and the Welsh and Northern Ireland assemblies.
At 6.30pm, Mr Edwards will hand over to the regional news rooms around England and the three Celtic nations, who will return to the London studio at 6.55pm for a summary of the national headlines before the end of the programme.
"There has been a metropolitan bias in news coverage," said Mark Popescu, editor of the new Six O'Clock News. "And now there are new institutions which we have to take account of. We have to be much more sensitive about the way different stories will play in Scotland, Northern Ireland and Wales."
There was outrage in Scotland last year when the BBCgovernors refused to give the country a separate national and international bulletin at six o'clock.