Abstract: Two experiments were conducted to discuss whether event-based prospective memory age-related declined, when prospective memory was embedded in the task of category judgment. Results of the first experiment showed no age deficits in event-based prospective memory, and there was no correlation between event-based prospective memory and free recall; but in the second experiment, the on-going tasks included color-judgment and category-judgment, the prospective tasks also included color-judgment and category-judgment. The results indicated that the congruence of on-going task and prospective memory affected performance of prospective memory. When they are all color judgments or category judgments, there were no differences between the young adults and the old adults. When they required different levels of process, age difference was significant. In conclusion, the relationship between the event-based prospective memory and aging was complex, it was determined by the character of even-based prospective memory

Key words: event-based prospective memory, congruence, age difference