This paper treated the problem of thematic development and cognition aspects of conversation. First of all conversation was developed around the mutually coordinated level themes among participants around theme in a big frame. In this development, leveled themes were formated while forming a certain hierarchy focusing on discourse segment. And they showed entrance, body, and exit. In addition, an aspect of theme continuation was more highlighted than it of theme change between each utterances in a small frame. And deepening theme has proved significantly more aspects of the transition to the next in the face of theme continuation. However, this paper was limited to some of the participating subjects were college students, leaving the limits did not consider having an intimate conversation situation.