Poetry means "one poem after another", for example:
He wrote a poem praising her loveliness.
He wrote a poem praising her beauty.
Poetry refers to "the floorboard of poetry" or "the art of poetry", for example:
Poetry helps to interpret life.
Poetry helps to explain the meaning of life.
2. The meaning is different.
Poetry can mean "poetry", but poetry does not have this usage, for example:
The dancer's movements are poetic.
The dancer's movements are full of poetry.
3. Different parts of speech.
Poetry refers to specific poems and songs, and it is a countable noun.
Poetry refers to the literary genre of poetry and is an uncountable noun.
"A poem" can be expressed by a poem or a poem, but not by a poem.