Abstract: Mortality salience effect is one of the most important assumptions of Terror Management Theory (TMT). It assumes that thoughts related to death can enhance the defence of an individual’s worldview. Uncertainty Management Model gives new explanation to mortality salience effect, pointing out that past researches overlooked the effects an individual’s uncertain feeling has on defense behaviors. After combining and discussing this theory with TMT, conclusion can basically be drawn that mortality salience has duplex effects on individuals. A duplex defense system will be launched after one’s thinking about his or her death. Future researches should focus on relationships between various kinds of defense modes.

Key words: mortality salience effect, terror management theory, uncertainty management model, worldview defense, uncertainty salience