Based on the theory of Korean broadcasting history，this paper divides the development of Korean documentary into five times. By studying Korean broadcasting awards at various times，it systematically analyzes the changes and trends of documentary themes at different times with the changes in Korean politics and society. We found that current events documentary has always been the most popular documentary theme in Korean broadcasting awards，and it still shows a growing trend. Other documentary themes change with the change of the times. Through the analysis of documentary themes，we can see the demand change of the Korean documentary market，to improve the understanding of Korean documentary.