区别就是两者意思是不一样，具体的不同如下

concept中文意思是adj. （围绕）某主题的为表达一种想法而创造的，n. 概念，观念！

It's not a question of some abstract concept of justice.

notion中文意思是n.想法缝纫用品一时的念头，突发的奇想

They have always looked askance at the western notion of democracy.