A critical biography is a critical writing about a character based on the materials of his life. In particular, the success of a review about a historical figure depends largely on reconciling the differences between the factual objectivity of life materials and the subjectivity of the critic's interpretations. In this article, we analyzed three books about Jeon Bong-Jun, the leader of the Donghak Peasant Revolution, to explore the issue of historical interpretation and how we can write his biography to extend Donghak's scope. The books selected for analysis are Critical Biography of Jeon Bong-jun (1996) by Shin Bok-Ryong, Critical Biography of Nokdu Jeon Bong-jun (2007) by Kim Sam-woong, and Jeon Bong-jun, Record of Revolution (2014) by Lee Yi-hwa. Our study went as follows. First, we examined the concept and significance of critical biography and presented the problem of objectivity in the interpretation of history. In the analysis of critical biographies of Jeon Bong-jun we summarized the characteristics of the three books, focusing on the purposes of writing the biographies, the views on Jeon Bong-jun's personality, leadership, table of contents, major issues, and appendices. Finally, we suggested as ways of writing a biography for Donghak expansion exploring various ways of improving the readability of biographies, making the most of the advantages of biography form, stronger portrayals of Jeon Bong-jun's ideas and personality, and re-establishing Jeon Bong-jun's views of the world.