The purpose of the present study was to investigate why rumors started, how rumors spread, and how the police prevented rumors in wartime Taiwan based on a large amount of police-related data. In addition, the present study aimed to reveal what people cared for, worried about, feared of, complained about, and hoped for in wartime Taiwan by analyzing content of the rumors and connecting the rumors with background of wartime.Based on the above analyses, it was established that, in wartime Taiwan, the police thought the rumors were attributed to changes in environments, mass agitation, public ignorance, and the enemy. Because of their negative effects on society during wartime, the rumors must be prohibited through persuasion and suppression done by the police. Additionally, an investigation of wartime people experience also revealed their fear and silence caused by the police's high-handed ways of controlling public opinion.