This is a preliminary- study on new warning method for the Human-Machine-Interactive operation environment.Human's operation under hearing same beat sounds are paid attention.Relationship between frequency of beat sounds and human's operation are analyzed.In his experiments,easy to express the human operation,Uchida-Kraepelin test are performed.The results of many experiments performed with a different beat sound show that performance of Uchida-Kraepelin test will be changed unconsciously shortly after beat frequency changed.