The model and businesswoman married the former stripper at a small ceremony in the Bahamas last week, having only been dating since December.
However, her lawyers are said to have drawn up the prenup in case her third marriage did come to an abrupt end, reports The Mirror.
A source said: "She loves Kieran and hopes this marriage lasts but realises there is a chance it could go the same way as her last two.
"She wanted to make sure she was covered as she has worked hard for her money."
However, the insider added that Kieran Hayler has not married Price for the money, but rather that he has fallen for his new wife.
"He's in this for love. He doesn't care about the cash," the source added.
Katie Price has revealed that she plans to sue the Sandals hotel where she got married, after the news of their ceremony was leaked to the press.
Last week, she defended her quick marriage to Hayler, saying that it was "only" her third one to date, having previously been married to Peter Andre and Alex Reid.