The main purposes of this article are to explore some of Vygotsky s discourses concerned with cognitive development and the practicable ways when applying them into instruction. Firstly, the article articulates Vygotsky s viewpoints about cognitive development. Next, it tries to analyze the implication of teaching based on Vygotsky s theory. Thirdly, the article discloses the probable problems when applying Vygotsky s viewpoints into instruction and tries to propose some practicable strategies that can solve them. These strategies can be seen as one kind of scaffolding that can advance students ability of problem solving.