The incident happened as he was singing "It Matters To Her" at the Colorado State Fair on Saturday.
McCreery was seconds into his performance when he spots the alleged assault.
"That's a lady you just hit, sir," McCreery said as he called on security to remove the man from the crowd.
"Get the heck out of here .... At a Scotty McCreery show, what are you doing?" McCreery said.
A spokesperson from the Colorado Department of Agriculture confirmed "an incident took place at the Scotty McCreery concert where a man assaulted a woman, and the performer stopped the show."
So far, nobody has been identified.
Scotty McCreery stops show after man reportedly hits woman in crowd