Empathy is widely regarded as a crucial pillar of human moraldevelopment that can promote fair behavior. However, recent research hasrevealed the complex relationship between empathy and fairness. This studyexamines the interplay between interpersonal factors and high-demandcharacteristics in modulating empathic differential responses in allocationbehavior and third-party punishment behavior, leading to two forms of unfairbehavior: “favoritism” and “deontological unfairness.” The neural and biologicalbasis of empathy-induced “favoritism” unfair behavior is associated with themodulation of oxytocin response and the ventromedial prefrontal cortex byinterpersonal closeness. In addition, the dual-process model of moral judgmentprovides a theoretical explanation for empathy-induced “deontological” unfairbehavior, with the neural mechanisms involving increased activation levels inthe ventromedial prefrontal cortex and amygdala, along with suppression ofneural responses in the dorsolateral prefrontal cortex. Future research shouldexplore a broader range of empathy types and components, integrate studies onspecific populations, and comprehensively elucidate the underlying cognitiveand neural mechanisms of empathy-related unfair attributes.