Abstract: Multilevel theory has becoming a new paradigm in organizational research. And the interaction between macro and micro phenomena can be studied in multilevel theory. After showing the origin of multilevel researches, the article introduced three unite-level constructs, five composition models of construct, and a decision-making frame. And the article explained the usefulness and the comparison of the four justified indexes (rwg、ICC（1）、ICC（2）、WABAI) that were constantly used. And at last, the article simply showed the three popular analysis procedures and comparison between them（WABA：within-and-between-analysis、HLM：hierarchical linear modeling、CLOP：cross-level operator）

Key words: multilevel theory, unite-level construct, composition model