Computer security depends on the user authentication method, and alphanumeric password is the most widely used method to protect users' privacy. However, users tend to choose short and simple passwords which will be broken easily, while secure passwords are difficult to remember. Graphical password is a promising solution to this problem, as psychologists have shown that images are more memorable than words or sentences. In this paper, we first categorized existing graphical password schemes into three kinds and then conducted a comprehensive overview of some schemes of a kind named recall-based. We also summarized the usability and security reported in some user studies of those recall-based schemes. Finally, some suggestions were given.