Diversity has been an important communication policy, but there are many different and confused definitions in previous researches. This paper tries to clarify the concept of diversity which has been discussed for a long time in media research. This paper also tries to propose a combined model of "diversity" to include different definitions and relationships based on previous literature reviews. In addition, this paper points out several categorization and statistic problems in content analysis and emphasizes that researchers should not over explain the results they found.