In order to reduce blast vibration, we usually use delayed blasting method.Recently, it became to be able to control delay time precisely within several, μ s. Based on such preciseness of initiation time, we studied nine setting methods of delay time for the purpose of reducing total ground vibration.As the results, we indicated setting method had influenced on peak particle velocity, predominant frequency and its amplitude remarkably and then discussed the results from point of view of blast vibration control.