I want to say that the simple syntax of a poem, makes it easy for the reader to understand. Is it correct to write
The simple syntax that is used, facilitates the comprehension of the poem.
Your sentence construction looks okay. However, you have not mentioned the easiness of comprehension that you were aiming for with the 'simplicity of the syntax'. So you might want to add that.
The simple syntax that is used, facilitates the easy comprehension of the poem.
Otherwise it looks pretty okay to me. Alternatively, you could also say :
The use of simple syntax in the poem, facilitates its easy comprehension.