In this report, effective voice parameters for announcement of disaster prevention were examined by changing the non-professional's normal speech in fundamental frequency, speed and/or amplitude. In a standard short announcement for disaster prevention, the three sentences are used; fact, state and command. Subjects judge the expressions of the synthesized speech. It was found that the first sentence (fact) should be faster, the second sentence (state), and the last sentence (command) should be higher in fundamental frequency.