The London double header, which will see Harlequins meet London Irish, and Wasps play Saracens, is predicted to supply more than half of the predicted figure.
Speaking at the launch of the Premiership season, Premier Rugby chief executive Mark McCafferty hopes attendances for the season to increase once again.
He said: "The prospect of 100,000 people watching our first round of matches is a very real one given the strength of ticket sales for the London double header and the likelihood of sell outs at other venues.
"Our attendances rose again last season to average over 10,000 per match for the first time ever, meaning over 1.3million people came to watch Premiership matches last season.
"We hope to build on that figure yet again, starting with 100,000 people at our round one matches."