本文以知识社会学方法，考察了拉斯维尔的宣传定义。本文发现，拉斯维尔在定义宣传时，背后受到研究方法、政治环境、学术取向等多种因素影响。从宣传定义的流变可以发现，拉斯维尔修正宣传定义的背后实则是发现了制约宣传的新因素。在宣传研究中，拉斯维尔逐渐转向了传播研究，但却始终没有放弃宣传研究。

Based on the Sociology of Knowledge method, this paper examines Harold. D. Lasswell’sdefinition of propaganda. This paper finds that the definition of propaganda was affected byresearch method, political environment, academic orientation and other factors in different historical periods. According to the history of propaganda conception,Lasswellrevisedpropaganda conception because he found new factors. In conclusion, Lasswell gradually turned to the communication study, but he never gave up propaganda research.