The Boeing 737-800 was en route from Kunming to Guangzhou when it reportedly began a steep descent from 28,000 feet before hitting a forested mountainous region.
Flightradar data showed the aircraft was in the air for just over an hour before it crashed.
The aircraft type involved is different from the Boeing 737 Max, which suffered two similar fatal crashes due to software malfunctions.
Shanghai-based China Eastern Airlines is the country’s second-biggest carrier by passenger numbers.