Last year, Long March-5 had successfully made its maiden flight in Wenchang.
China's state-run Xinhua news service announced about 45 minutes after liftoff that the launch had failed.
The Long March-5 Y2 lifted off early in the evening from the Wenchang Space Launch Center, in what was seen as the last drill before the same rocket type carried a lunar probe later this year with the goal of returning from the Moon with samples. An upper stage attached to the satellite was later able to correct the orbit.
Separation of the satellite and the second stage of the Long March 5 was due to take place at T+1714 seconds, almost 30 minutes after launch. The launch, broadcast live by Chinese media, appeared to go as planned, but those broadcasts ended prior to any announcement of separation of the rocket's payload, the Shijian-18 communications satellite.
Long March-5 Y2 rocket is capable of lifting 25 tonnes into a low earth orbit and a 14 tonne class of communications satellite.
Weighing 7.5 tonnes, Shijian-18 is the heaviest satellite China has launched into space. At that time, China said it was the most powerful launcher it had yet developed. The rocket uses environmentally friendly fuel, including kerosene, liquid hydrogen, and liquid oxygen, rather than highly toxic propellants, the report said. The next Long March 5 launch was scheduled for November, carrying the Chang'e-5 spacecraft.
China says launch of Long March-5 Y2 "unsuccessful".
According to a launching site official, specialists are now carrying out the last testing and fuel the rocket, while the weather conditions are expected to be fine for the launch.