On Friday he will address the country in an appeal to be made from the Olympic stadium in London.
Cameron is likely to claim that splitting up the country will have a bad affect on all, sources say.
Scotland's Deputy First Minister, Nicola Sturgeon, last night said the Prime Minister's bid to gather support for the no votew was "shameful" and "cowardly".
Scotland is due to hold a referendum on September 18, in which Scots will decide whether or not they want to separate from the United Kingdom.
At present poll suggest that around 40% of Scots oppose independence, but this is likely to wane as Scottish minister Alex Salmond campaigns for a yes vote.
UK Foreign Minister William Hague recently warned Scotland that if they became independent they would be banished from the European Union.
However, UK Prime Minister David Cameron is also said to be preparing his own referendum for 2015 regarding the UK's membership to the EU.