There are two paradigms about research of justice judgment. One is relational-cognitive model,in which justice judgment is thought to be caused by moral reasoning.The other is subjective-emotional model in that it emphasizes the importance of emotional influence.But there are few empirical studies to resolve the distube between rationalist and intuitionist model.Based on the reseach of emotion and cognition and uncertainty management theory,this study focused on the issue of how people form justic judgments and under what conditions emotion as information may serve a valuable role with 2 experiments. Experiment 1 explored the effect of emotion on judgment of outcome justice.200 students from two universities participated in the experiment and were randomly assigned to one of the conditions of the 2(emotional state: pleasant vs angry) ×4(outcome of other participant:unknown vs. equal vs. worse vs.better)factoral design.The design was balanced with an equal number of participants taking part in each of the eight conditions. Experiment 2 analysized the role of emotion on judgment of procedural justice.120 students from two universities were randomly assigned to one of the conditions of the 2(emotional state: pleasant vs angry) ×3(procedure:no-voice information vs. explicit no voice vs. voice)factorial design. These two experiments found uncertainty mediated the relationship between emotion and justice judgments. Under the conditions of information uncertainty, emotion acted as information. Individuals with positive emotion easily tended to make just decisions. And individuals with negative emotion inclined to unjust judgments. But under certainty conditions, the effect of emotion was not significant. Justice judgments relied on cognition.