Abstract. Although Hadoop is widely used, its full potential is not yet put to use because of some issues, the small files problem being one of them. Firstly, the paper analyses the causes of the small files problem of Hadoop. Then, the current program to solve the small files problem are introduced, including Hadoop own programs and other application-specific solutions, and analyzes the advantages and disadvantages of various options. Finally, we present two research ideas, one is to use a combination of RDBMS and Hadoop; Another is to make the "Datanode" caching some metadata of the small files.