The girl was suffering from a medical condition called hydrocephalus, which causes a buildup of excess cerebrospinal fluid in the brain.
The condition left her with a head weighing about 20 kg, while she herself weighs only 32 kg.
Doctors said she is recovering steadily after the 3D-printed titanium alloy skull was implanted, becoming the first person to have her cranium successfully reconstructed by by 3D printers.
Han Han underwent the 17 hour surgery on Wednesday at the Second People's Hospital of central China's Hunan Province and is under observation, said neurosurgeon Kuang Weiping, who is in charge of her treatment.
Also Read
Due to the heavy weight, parts of her brain suffered serious infections and she lost sight because her optic nerve was affected.
Kuang said they believed her skull was likely to rupture as infected parts became thinner and only the "brain-shrinking" operation could save her life.
During the process, neurosurgeons peeled her scalp and skull, then drained the fluid in her head.