Social media not only changes the traditional communication environment but also brings new changes to agenda-setting. The main body of agenda-setting has shifted from the traditional media to the politicians, political parties and grassroots people. With the increasing use of social bots in public opinion manipulation and political election interference, whether they can participate in or influence agenda-setting has become an urgent concern. So far, there has been less literature focusing on engagement in agenda-setting for social bots. This paper studies the social media discussion content of the South Korean presidential election, determines the participation of social bots, and explores the connection between media agenda, bot agenda, and public agenda from the perspective of agenda setting. This study finds that while the main agendas of media, social bots, and the public are not the same, their agendas are relevant. In addition, the media agenda is not timely ahead of the bot agenda and the public agenda, and the time order only appears between the social bots and the public.