Loch finished .205 seconds ahead of Andi Langenhan, who won the World Cup in Koenigssee last weekend. Johannes Ludwig, who had improved the track record to 53.429 seconds in the first run ahead of Loch, dropped to third place in the second run.
Samuel Edney of Calgary was sixth.
Loch leads the overall World Cup rankings with 285 points ahead of Langenhan with 245 and Ludwig on 225. Loch posted his first career victory on the Altenberg track and also captured his third world title there. He now has 12 career wins.
Germany also won the team relay event.