Making has been considered as an important way to effectively promote STEM education in informal learning environment. Making is growing and gradually presents a number of affordances that are conducive to STEM teaching and learning. However, studying STEM through Making within out-of-school context is still not fully mature, so STEM educators are facing challenges. Based on constructionism and embodied cognition, this essay will discuss affordances from three perspectives (constructionism pedagogy, engagement in STEM-related practice and playfulness). The current challenges about learners’ participation and assessment are also analyzed. Aiming at current challenges, suggested teaching and assessment methods are put forward.