Injustice is a common phenomenon which has a negative impact on not only the employees’ job involvement, but also their career success, and ultimately has an undesirable impact on the organization. Furthermore, managers and employees mostly are concerned about pay situation among many factors that cause the perception of unfairness. Nowadays, the majority of studies empirically verified how pay dispersion between subordinate relationship affects employees’ behavior. Few scholars explained the relationship between perception of justice affected by pay dispersion and job involvement based on equity theory. Thus, this study helps enterprises to understand the employees’ psychological perception of pay dispersion, so that managers can balance the internal salary gap and ameliorate the employees’ justice perception, and motivate employees to involve into work.