"At 2:55 PM local time (6:55 GMT) on June 19, the Tienzhou-1 cargo spacecraft flew a full circle around the Tiangong-2 space lab and completed its second docking with the space lab," the agency said in a statement.
The Tianzhou-1 spacecraft was launched on April 20 from south China's Hainan Province and completed its first automated docking with the Tiangong-2 space lab on April 22.
After its launch, China said the Tianzhou-1 spacecraft is expected to dock with Tiangong-2 three times.
China plans to launch a new module of its space station in 2018 for testing respective technologies. The station is expected to be fully functional by 2022.