One of Usher's accusers has to keep her nose out of his bank accounts ... TMZ has learned.

Laura Helm wanted the courts in Georgia to block Usher from hiding assets to make sure she could collect if she wins her $20 million lawsuit -- but the judge shut her down.

In docs, obtained by TMZ, the judge said Helm has no right to say a peep about Usher's finances because he doesn't owe her anything yet. Further, Helm failed to present any legal precedent for the judge to block Usher at this stage ... according to the docs.

Translation: Your request is BS, and denied. 

Big W for Usher's Atlanta counsel, Steve Sadow.