The Five-hundred-meter Aperture Spherical Telescope, or FAST, is the size of 30 football fields and has been hewed out of a mountain in the poor southwestern province of Guizhou.
Scientists will now start debugging and trials of the telescope, Zheng Xiaonian, deputy head of the National Astronomical Observation under the Chinese Academy of Sciences, which built the telescope, said.
"The project has the potential to search for more strange objects to better understand the origin of the universe and boost the global hunt for extraterrestrial life," Reuters quoted Zheng as saying.
The 1.2-billion yuan ($180 million) radio telescope would be a global leader for the next one to two decades, Zheng added.
The telescope, which has taken about five years to build, is expected to begin operations in September.
Advancing China's space program is a priority for Beijing, with President Xi Jinping calling for the country to establish itself as a space power.
China insists its program is for peaceful purposes, but the US Defense Department has highlighted China's increasing space capabilities, saying it is pursuing activities aimed to prevent adversaries from using space-based assets in a crisis.