Domracheva, who won bronze in the individual event at the Vancouver Olympics, quickly made up a 32-second deficit at the start and never looked back, shooting an almost perfect 19 out of 20.
Norway's Tora Berger made up for Saturday's disappointing sprint as she took silver and Slovenian Teja Gregorin claimed bronze.
Slovak Anastasiya Kuzmina, who won the sprint, made two mistakes on the shooting range and came sixth.
Domracheva finished with a massive 37.6-second advantage over Berger and Gregorin was 42 seconds off the pace.
Berger, who arrived in Sochi looking for a grand slam of titles, was in better form that during the sprint in which she finished 10th.
She stayed in the main pack in the first part of the race, surging into podium contention only after the first standing shooting segment.
A missed target in the final shooting was not enough for Gregorin to catch up as Berger earned Norway their fourth medal of the day at the Laura Biathlon and Cross-country complex after her cross-country team mates shone in the sprint events.
The next women's event will be the 15km individual, where Berger will defend her Vancouver title.
- Sports & Recreation
- Tora Berger
- Teja Gregorin