The billionaire is in talks with Rangers chief executive Charles Green about a joint venture to sell replica strips through Ashley's Sports Direct empire.
"If Mike Ashley is interested in investing in Rangers, then the fact of the matter is he looks to be a very successful businessman," said Ibrox boss McCoist.
"It would be great to have people of that pedigree contributing to the club moving forward.
"I don't know enough about any proposed deal but I know Charles Green has been in meetings for two to three weeks now and I'm led to believe they have been successful meetings.
"So if we were to get a guy like (Ashley) with a proven track record on board then good."