Shortly after midnight, the fire in the three-story building broke out on Tuesday.
The police arrested a 32-year-old man for alleged arson. He reportedly blocked the only exit of the bar with a motorcycle before opening the fire.
Videos circulating on social media showed audiences watching intense flames flooding the bar.
Police were first alerted to the fire at 00:30 local time on Tuesday (16:30 GMT Monday). According to Qingyuan police on the microblogging website Weibo, it was dropped until 00:55.
The alleged arsonist Liu Chunlu, who was reported to have suffered burn injuries, was arrested the next morning
According to the state television channel CCTV, he had blocked the only entry and exit points and then lit a fire.
The authorities offered a reward of 200,000 yuan to anyone providing information about the suspects
Twenty-two people were killed last year after a fire broke out in a two-story house in eastern China. The police later arrested a man for allegedly setting fire to the residential building.
In 2016, 17 people were killed aboard a bus in a suspected arson attack and one man was later arrested in connection with the incident.