Abstract: Quantum suicide experiment is a kind of ideal experiment deriving from the hypothesis of many-worlds interpretation (MWI)， which is regarded as a decisive experiment on the many-worlds interpretation and traditional interpretations of quantum mechanics. The controversy over the experiment focuses on three aspects: how to define the branches， how to define the probability and how the experimenter chooses his/her position. Among them the branch issue is derived from the many-worlds interpretation itself. However， the controversial root of the other two issues is that they fail to realize that the branches are not possible worlds but inevitable parallel worlds， whose core is to redefine the probability and guarantee the identity of consciousness. While the experiment can't verify the many-worlds interpretation， it reveals many problems and contradictions in terms of verification， probability and trust.

Key words: quantum suicide experiment, many-worlds interpretation, branch world, subjective probability