Officials in Shenzhen, which borders Hong Kong, also set fire to illegal drugs worth e15 million.
Four men were executed in Guangzhou, the capital of southern Guangdong province, after being sentenced to death at rallies in four Guangdong cities.
Three others were executed in Wuhan, a city in central Hubei province, for trafficking in heroin and opium.
In Wenzhou, on the southeast coast, a court sentenced to death four people convicted of involvement in a heroin trafficking ring in the southwestern province of Yunnan.
Yunnan borders the heroin-producing “Golden Triangle” which includes parts of Burma, Laos and northern Thailand.
A court in Shenzhen sentenced at least two convicted drug traffickers to death, including a “big Hong Kong drug lord” identified as Li Qingyuan, , the state-run newspaper Beijing Evening News reported.
Similar rallies and executions were held in other Chinese cities, including Xi’an and Hangzhou.