He says it would be catastrophic for both the club and the city itself if Alan Shearer's side - currently third from bottom in the table - failed to stay in the top flight.
But if the worst-case scenario does occur and they do go down, he believes current chairman Mike Ashley will invest to take the club straight back up.
Speaking to Sky Sports News, Shepherd said people were presently having a pop at the club.
Shot"You've got to remember we've been in the Premier League for 15 years and when they see us struggling like this, everybody wants to have a shot at Newcastle," he said.
"But at the end of the day, we are where we are and we'll get out of this."
He agreed it would be catastrophic for the club to drop out of the Premier League.
"It would be and it would be bad for the city - we have huge business interests in the city so it wouldn't be any good for us either so I'm just keeping my fingers crossed that we stay up."
InvestAsked if he thought there was a plan in place if the Magpies do go down, Shepherd replied: "Yes I'm sure Mike will put the money in to invest in the team and get the team back up if they do go down but as I say, I'm confident they will stay up."
He also believes Shearer is the right man for the job at St James' Park, although "perhaps he was brought in a little too late but time will tell on that."
He added: "But I'm confident whatever happens he's the future manager for Newcastle."