Why some of the organizations in any industry in comparison to others are more profitable and why the performance of some organizations is more desirable and lucrative? Why some of the organizations tolerate political, economic and social changes and overcome them easily, while on the contrary some organizations fail easily and can not continue their business? In other words, how successful organizations gain competitive advantage? Since in each organization, the ultimate goal of strategy is achieving competitive advantage, for answering to the mentioned questions, there is a need to analyze the process of strategic planning. The purpose of this article is to analyze the process of strategic planning and factors influencing it, so that organizations by means of that identify the concepts and methods of strategic planning correctly and they will be able to formulate strategy in condition of uncertainty and intense competition and can protect themselves against environmental changes. Also, in this article, factors and dynamics that relate to the initiation of strategic planning efforts within organizations and the relationship between flexibility, strategic planning and organizational performance have been analyzed.