The existing research on relationship between emotion and prospective memory often focused on a single aspect, which were the ongoing task materials or the emotional valence of target cues to explore effects of prospective memory processing mechanism. The emotion of one variable could affect prospective memory through the other variable, so controlled the emotional valence under a single condition had some obvious defects. In addition to the difference of the task materials and prospective memory property, it was difficult to grasp the relationship between emotional valences and mechanism of prospective memory generally. In the current study, we used the dual-task paradigms and materials on emotional images and emotional words to explore the effect of consistency on the process of event-based prospective memory about emotional valences of ongoing tasks and target cues, and emotional valences of prospective ingredient and retrospective ingredient from the prospective memory at the same time. Experiment 1 selected 64 college students as subjects, adopted 2(emotional valences of ongoing tasks: positive valence/negative valence)*2(emotional valences of targets cues: positive valence/negative valence) mixed experimental design, among which the emotional valences of ongoing tasks is within-subject variable, the dependent variables were the reaction times and accuracy of current tasks and prospective tasks. Experiment 2 selected 64 college students as subjects, adopted 2(emotional valences of prospective ingredient: positive valence/negative valence)*2(emotional valences of retrospective ingredient: positive valence/negative valence) mixed experimental design, among which the emotional valences of prospective ingredient is within-subject variable, the dependent variables were the reaction times and accuracy of current tasks and prospective tasks, and the accuracy of prospective ingredient and retrospective ingredient. The result of Experiment 1 revealed that the accuracy of prospective memory about positive valence was higher than negative one, and the accuracy of prospective memory was higher when emotional valences of ongoing tasks is opposite of the emotional valences of prospective tasks. On the contrary, it was lower. The result of Experiment 2 revealed that the main effect and the interaction of emotional valences of prospective ingredient and retrospective ingredient were not significant, but the accuracy of prospective ingredient was affected by both emotional valences, it was higher when both emotional valences were inconsistent. The above results come to two conclusions: 1) the performance of prospective tasks and prospective ingredient were better when emotional valences of both tasks and both ingredients were inconsistent, because target cues and prospective ingredient were more prominent in this case, which could be called Opposite-valence Enhancement Effect. 2) In event-based prospective memory, emotion affected the prospective memory processing as a kind of additional clues.