Red China vs Communist China

Red China and Communist China both are nouns.

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

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

Red China and Communist 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, mainland China, People's Republic of China, PRC.

Red China (noun)	Communist 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