The recorder was found 1.5 meters (5 feet) underground, according to emergency response headquarters for the accident.
The Boeing 737-800 flight, with 123 passengers and nine crew members, was flying from the southeastern Kunming city to Guangzhou, a port city near Hong Kong, when it crashed in a mountainous area in southern China on Monday.
The black box, which is estimated to record flight data such as the aircraft's route, speed and altitude, may shed light on the cause of the accident.
Search at the crash site outside the Wuzhou city, a hilly and forested region, are difficult to maintain due to ongoing rainfall in the sub-tropical region. Teams are draining collected water with pumps to clear the site for work.
Authorities late Saturday announced there were no survivors from the crash.
On Wednesday, officials said a black box was found, but it was "badly damaged."
Weather was not hazardous when the plane crashed, according to authorities, and the flight had maintained normal communication with air traffic control unit until its sudden fall.
The aircraft had met the requirement for flying before its departure and the pilots were in good health, an official of the China Eastern Airlines earlier said.