The Liverpudlian overwhelmed the former Olympic champion to the delight of his home fans at the Echo Arena with a flurry of bombs which ended the fight after only 82 seconds. While the 8,000 fans cheered Price they also booed Harrison for his poor show.
A big right from Price started the barrage and saw Harrison wobble and Price then followed that up with five more expertly picked out shots to the head, the final one of which floored Harrison.
With the victory Price improves his professional record to 14-0 and bigger fights are sure to come for the 29-year-old.
Price and his promoter Frank Maloney both said after the fight that they would like to take on fellow unbeaten British heavyweight Tyson Fury.
However, Price's next fight will be against former British, Commonwealth and European champion Matt Skelton on December 8. Skelton enjoyed a second-round win over Croatian Jakov Gospic on the undercard.
Harrison's already damaged reputation would appear to be completely in tatters now after another humbling loss.
The gold medallist at the Sydney Olympics now has a 28-6 and the 40-year-old will be expected to retire after this latest humiliation.
Despite the ease of his victory, Price did still pay tribute to Harrison.
"We need to remember this man won the Olympic gold medal for his country and inspired a generation of boxers," he said.
Meanwhile, James DeGale retained his European super-middleweight title with a unanimous points victory over Hadillah Mohoumadi.
DeGale was made to work hard for his 13th win, with one defeat, as he took some punishment from the Frenchman before winning 119-109, 117-111 and 116-112 on the judges' scorecards.