The elderly experiencing all kind of loses in their advanced stage of life, and internalizing the widespread negative views toward their age group at large, compromise their subjective well-being. In this study, based on the elderly’s preference for positive emotions, a re-experiencing gratitude intervention was designed to enhance the subjective well-being of the elderly. 75 elderly people over the age of 55 were assigned to one of the following four groups: Daily Gratitude Group, to write down their grateful experiences from their daily life; Life Gratitude Group, to recall those grateful events happened in their past; Daily Importance Control Group, to record their daily important events; No Treatment Control Group, only to fill up a questionnaire. Analyzing change scores on the grateful emotion, positive emotion etc. scales after seven weeks of writing, the positive emotions of Daily Gratitude Group were enhanced, compared with that of No Treatment Control Group, and this effect was mediated by grateful emotions. It is revealed that, just prompting the elderly to pay more attention to their daily grateful events makes them experience more grateful emotions, and it helps them face up to negative situations in their late years and maintains their subjective well-being. However, Life Gratitude Group was not expected to enhance the subjective well-being, but Daily Importance Control Group was unexpectedly to enhance it, the researcher also explained these effects through experimental data. Finally, it also explains how the results of this study are applied to senior education.