With the degree of the aged phenomenon becoming more serious in our country, the health and cognitive problems of the elderly gradually become the focus of social attention. Previous studies found that not only the outgroup had negative stereotypes against the elderly, such as weak, obstinate and forgetful, but also the elderly themselves thought they were discriminated by outgroup because of their decline in memory, cognitive ability and creativity. That is to say that the elderly has negative meta-stereotypes. Meta-stereotype is the belief or awareness that ingroup members holds what outgroup members think of them. The valence of meta-stereotype is mostly negative, and meta-stereotype is more likely to be activated in the vulnerable group, for example, the elderly group. Previous studies have found that the activation of negative stereotypes will lead to negative cognitive effects, and the activation effect will be different under different difficulty cognitive tasks. Meta-stereotypes are more negative than stereotypes. Therefore, this study aims to explore the effect of activated negative meta-stereotype on cognitive performance among the elderly under two different difficulty N-back tasks. Our hypothesis was: (1) The activation of negative meta-stereotype will reduce the elderly’s cognitive performance. (2) When the negative meta-stereotype is activated, the performance among the elderly in different difficulty cognitive tasks is different. We tested the manipulation of the negative meta-stereotype among the elderly through a pilot study, and found that the activation of the negative meta-stereotype triggered significantly more irritability. We use another pilot study to test the applicability of the difficulty of cognitive load task among the elderly. Finally, the low cognitive load task (0-back task) and the high cognitive load task (1-back task) were selected to examine the cognitive effects of the activation of negative meta-stereotype among the elderly. In the formal experiment, 59 elderly people (mean age 72.87 years old, SD=7.75) were randomly assigned to a negative meta-stereotype group or a control group. A 2 (meta-stereotype manipulation: negative meta-stereotype activated group, the control group) × 2 (task difficulty: low cognitive load, high cognitive load) mixed-designed experiment was used in this study. Results showed that, 1) the average accuracy of participants in the negative meta-stereotype group was significantly lower than control group, and the average accuracy of high cognitive load task was significantly lower than low cognitive load task; 2) the average reaction time of negative meta-stereotype group was significantly longer than that of the control group, and the average accuracy of high cognitive load task was significantly longer than low cognitive load task; 3) the interaction effect between group and cognitive load level on reaction time was marginally significant, which suggested the reaction time of the negative meta-stereotype activated group was significantly longer than the control group in high cognitive load task while this difference was not significant in low cognitive load task. In general, the results show that the activation of the negative meta-stereotypes have negative cognitive effects among the elderly.