The Czech world champion and hot favourite, who stunned the world of alpine skiing by capturing gold in last week's super-G, recorded an aggregate time of one minutes, 28.90 seconds for her two runs -- more than a second ahead of her nearest rival.
Russian Alena Zavarzina, bronze medallist in Sochi four years ago, was second quickest in 1:30.16 with Germany's Selina Joerg qualifying third in 1:30.27.
Ledecka is looking to become the first woman to win gold medals in different sports at the same Winter Olympics.
Haug did the cross country and Nordic combined double at the 1924 Olympics and Grottumsbraten won the same events at the 1928 Games.