The last Emperor Puyi abdicated from the Qing throne in 1911, but refuses to be forgotten. He was first shortly restored as Emperor to the Qing throne by a warlord in 1917, though that lasted only 12 days; then he was again installed as the emperor of Manchukuo, a puppet of Japan in 1934.
So technically, the land known as China last had a monarchy in the Empire of Manchukuo, abolished in 1945 following the defeat of Imperial Japan.
The last Emperor Puyi abdicated from the Qing throne in 1911, but refuses to be forgotten. He was first shortly restored as Emperor to the Qing throne by a warlord in 1917, though that lasted only 12 days; then he was again installed as the emperor of Manchukuo, a puppet of Japan in 1934.
So technically, the land known as China last had a monarchy in the Empire of Manchukuo, abolished in 1945 following the defeat of Imperial Japan.