“教什么”是课堂教学的中心,“教什么”始终比“怎么教”重要.当“怎么教”凌驾于“教什么”之上时,课堂教学就可能出现“华而不实”的现象.而“教什么”首先关涉到教师的学科专业素养.舒尔曼指出,教师怎样理解学科知识对教学十分重要,专家型教师教学的成功,主要基于对学科知识的通透理解,但这一问题被以往的研究者忽视了.对于中小学数学教师而言,其专业素养的自我研修和提高,可以着眼于深度、广度和高度,从以下六个方面的维度来展开. “What to teach ” is the center of classroom teaching, “What to teach ” is always more important than “how to teach ” when “how to teach ” over Shurman pointed out that teachers’ understanding of subject knowledge is very important to teaching and the success of teaching by expert teachers is mainly based on the fact that “teaching what” is related to the subject’s professional accomplishment. Understanding of subject knowledge, but this problem has been neglected by the previous researchers.For primary and secondary math teachers, the professionalism of self-training and improvement, can focus on the depth, breadth and height, from the following six Aspects of the dimension to expand.