Red China vs People's Republic of China

Red China and People's Republic of China both are nouns.

Word	Noun	Adjective	Verb	Adverb
Red China	Yes	No	No	No
People's Republic of China	Yes	No	No	No

As nouns, Red China and People's Republic of China are synonyms defined as:

Red China and People's Republic of China: a communist nation that covers a vast territory in eastern Asia; the most populous country in the world

Other synonyms of Red China include Cathay, China, Communist China, mainland China, PRC.

Red China (noun)	People's Republic of China (noun)
a communist nation that covers a vast territory in eastern Asia; the most populous country in the world	a communist nation that covers a vast territory in eastern Asia; the most populous country in the world