Being of importance for classical electromagnetism,Faraday's thoughe of lines of force plays a vital role in the generation of the electromagnetism of Maxwell.Based on Faraday's Diary and other correlated materials,this article analyses and discusses the formation and development of Faraday's thought of lines of force and some other correlated questions,elucidates the tight link between Faraday's thought of lines of force and his experimental researches,and illustrate the basic content and significance of Faraday's thought of lines of force.