The US skier blew away the field with an opening run of 1:18.80minutes to open up a 1.28-second lead ahead of Alexis Pinturault, with Marcel Hirscher back in third.
After fog caused a brief delay to proceedings Hirscher, who has been the dominant force in the men's Giant Slalom this season, jumped ahead of Pinturault in the second run to finish second but the Austrian could not catch Ligety.
The leader went into the second run with a time of 1:21.46mins to beat and he cruised to victory, with a comfortable winning margin of 1.51secs.
Pinturault was a further 0.18secs back in third, with Sweden's Matts Olsson producing a solid second run to finish in fourth.
Hirscher will head to the Winter Olympics in Sochi still on top of the Giant Slalom leaderboard but Ligety's performance in Switzerland makes him the form skier.