This paper analyzes the process of performance evaluation by the managers holding different implicit person theory. The results indicate that the managers holding the entity theory choose, code and organize the information to facilitate the trait judgment for the initially poor performance and attribute the poor performance to the employee while the managers holding incremental theory show no bias. When facing the performance improvement, the managers holding entity theory emphasize more on the environment change, ignore the change of employee themselves and acknowledge the improvement less than managers holding incremental theory.