An enthusiastic Hong Kong crowd cheered new recruit David Beckham's every touch, although the England captain, playing in his preferred right midfield role, had a subdued game.
His best moment came in the 34th minute when a trademark crossfield pass picked out Ronaldo and the Brazilian striker scored his second goal of the game.
Real had the ball in the net as early as the second minute when Hong Kong 'keeper An Qi failed to hold a Roberto Carlos shot and Spanish forward Raul pounced on the rebound, but the effort was ruled offside.
Portuguese international Luis Figo opened the scoring from the penalty spot five minutes later after Roberto Carlos was brought down in the area.
Ronaldo then rifled in a left-foot shot in the 13th minute after being released by a slick pass from French playmaker Zinedine Zidane.
Chinese international Wang Peng scored with a powerful header in the 26th minute as Real did not have things all their own way.
But their joy was shortlived as two goals from Ronaldo and Raul within the space of two minutes put the visitors firmly back in the driving seat.
Li Yao rounded off the scoring in the first half stoppage time when he shot home after the ball broke to him from a corner.