Facing executions set for Friday are Naw Kham, identified as a Myanmar drug lord, and three accomplices, whose death sentences were upheld by a court in December.
A court in Kunming in southwestern China's Yunnan province Wednesday said the four will be executed in the city, the official Xinhua News Agency reported.
The other three were identified as Hsang Kham of Thailand, Yi Lai, who is stateless, and Zha Xika of Laos.
Xinhua said the court rejected their appeals and upheld the death sentences. China's Supreme Court, which later reviewed their cases, signed an execution order, Xinhua reported.
The lower court has already arranged for Thai and Myanmar consular officials and relatives to meet with the convicts, the report said.
In the December decision, another suspect's death sentence was upheld with a reprieve, while a sixth suspect was given an eight-year prison term.
All six were convicted of intentional homicide, drug trafficking, kidnapping and hijacking.
Naw Kham was accused of being the head of the largest armed drug-trafficking gang on the Mekong River, which flows through China, Laos, Myanmar, Thailand, Cambodia and Vietnam.
Naw Kham's gang was accused of attacking two Chinese cargo ships in October 2011, killing 13 Chinese sailors. The gang also was accused of being involved in a kidnapping-for-ransom case targeting Chinese citizens on the Mekong.
Official Chinese media reported a joint police operation by China, Laos, Myanmar and Thailand led to the gang members' arrest last year.