1. A method for waking up an electronic apparatus using voice trigger, comprising: receiving a current voice signal; extracting a current voice feature of the current voice signal; determining whether a previous voice feature of a previous voice signal is stored; wherein if it is determined that the previous voice feature is stored and a degree of similarity between the current voice feature and the previous voice feature is larger than or equivalent to a similarity threshold, (A) adjusting a confidence threshold according to a false acceptance situation or a false rejection situation corresponding to the previous voice feature, or (B) determining whether to wake up the electronic apparatus according to the false acceptance situation or the false rejection situation corresponding to the previous voice feature; wherein if it is determined that the previous voice feature of the previous voice signal is not stored, then the method further comprises: comparing the current voice feature with a key phrase voice model using a matching algorithm to obtain a confidence score; determining whether the confidence score is larger than or equivalent to the confidence threshold; waking up the electronic apparatus if the confidence score is larger than or equivalent to the confidence threshold; and not waking up the electronic apparatus if the confidence score is smaller than the confidence threshold; wherein after waking up the electronic apparatus, the method further comprises: (1) determining whether the current voice feature corresponds to the false acceptance situation according to a user interaction and range of confidence score; (2) if it is determined that the current voice feature corresponds to the false acceptance situation, then the current voice feature is stored and the confidence threshold is adjusted according to the user interaction; wherein the user interaction comprises a frequency of consecutive false acceptance, and the step of adjusting the confidence threshold according to the user interaction comprises: (1) determining whether the frequency of consecutive false acceptance is larger than a frequency threshold; and (2) increasing the confidence threshold if the frequency of consecutive false acceptance is larger than the frequency threshold.