Communist China vs Red China

Communist China and Red China both are nouns.

Word	Noun	Adjective	Verb	Adverb
Communist China	Yes	No	No	No
Red China	Yes	No	No	No

As nouns, Communist China and Red China are synonyms defined as:

Communist China and Red China: a communist nation that covers a vast territory in eastern Asia; the most populous country in the world

Other synonyms of Communist China include Cathay, China, mainland China, People's Republic of China, PRC.

Communist China (noun)	Red 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