Does one page LOR hurt my chance of getting to graduate school I recently asked from the professor whom I have done research with him and I also did great in his class for LOR. He agreed to write a positive letter of recommendation for me however when I talked to him further he said his letter is going to be one page double spaced. I am thinking this is really short letter according to some pages in the internet and also a post in this page

How long should letters of recommendation for students be?

Do you think this will hurt my chance of getting into top graduate school in US?
One page double-space sounds like your professor is willing to say good things, but doesn't have all that much to say.  That's not going to be a particularly strong letter of recommendation, but it's better than not having a letter.