The charred remains of the plane lay broken on the tarmac near the terminal after the flames were extinguished, an hour after the explosion.
The nose of the plane sagged on its side, while the tail -- emblazoned with the airline's pink plum blossom symbol -- was intact at the other end. In between, the blackened remains of the interior could be seen, with much of the roof of the plane gone.
Early investigations raised the possibility that leaking fuel may have caught fire.
"We don't have any information that suggests the accident was linked to terrorism. There is a possibility of the engine exploding and catching fire due to a fuel leak," a Naha airport police official told Reuters. One member of the ground crew had been injured, Kyodo news agency reported.
The airline said the plane, which had 157 passengers and eight crew, had just undergone scheduled maintenance.
"Everything was working according to normal procedure. There was nothing wrong during the flight," China Airlines spokesman Johnson Sun told reporters.
China Airlines has a troubled safety record with four deadly accidents in the past 13 years, including a crash in the Japanese city of Nagoya in 1994 in which 264 people were killed.
Okinawa is a popular spot for beach holidays and the number of visitors to Japan from other parts of Asia has increased in recent years, with the lifting of visa restrictions.