Mr Bush has made history by being the first ever US President to come to Britain on an official state visit.
This means he's been specially invited by the Queen.
While he's in Britain he will enjoy a ceremonial welcome, a formal banquet and private lunch with the Queen.
Protests
But not everyone is pleased to see Mr Bush.
Protest marches are expected in London and 14,000 British police will be involved in keeping Mr Bush safe.