Over 700 people came to see the Liaoning off, as a departure ceremony was held by the local government.
The vessel arrived in Hong Kong on Friday carrying a squadron of J-15 fighter jets and helicopters, and accompanied by a fleet of Chinese warships including destroyers Jinan and Yinchuan and frigate Yantai.
China’s first aircraft carrier was open to the public for the first time on Saturday and Sunday.
About 50,000 people visited the fleet and some 4,000 visitors were allowed a one-hour tour of designated areas of the carrier as well as its ship-borne weapons.
On Monday, crew members from the Liaoning, together with the People’s Liberation Army’s (PLA) Garrison in Hong Kong, visited a care home for the elderly.
"These elderly people have contributed a lot to Hong Kong’s development," said crew member Zhao Jinlu. "I am glad to see they are well cared for. I want to talk to them and learn how to take better care of the old people in my family."
"These events have been held for more than a decade. They have helped tighten ties between the PLA and the Hong Kong people," said Gao Feng from the PLA Hong Kong Garrison.
The Liaoning, which entered service in the PLA Navy in 2012, is a refurbished aircraft carrier built from the hull of a former Soviet Union ship bought from Ukraine. It was China’s only aircraft carrier until April 2017, when the country unveiled its first homemade carrier, the Type 001A.
"We take hate crime very seriously and actively investigate all incidents reported to us," it added.