Based on the criterion of the classification of rock mass

the characteristic of the medium which behaves as the carrier of the seismic wave due to blasting is quantified.Distinct Element Method（DEM） is used to analyze the process of the attenuation of the seismic wave due to blasting in the medium.The determination of the blasting loading

damping and relevant parameters is detailed in the numerical modeling.The influence of the characteristic of the medium on the attenuation law of the velocity of the vibration due to blasting and on the value of K、α in the empirical formula are studied.It reveals that the velocity of the vibration due to blasting decreases rapidly in the near field and slowly in the far field.When the medium is classified as Ⅰ～Ⅲ

K increases with the decrease of the quality of rock mass.For medium classified as Ⅳ～Ⅴ

there is no definite rule for K to follow.Generally speaking

α increases with the decrease of the quality of rock mass.The variation K and α is approximately the same as that of the velocity of the vibration due to blasting.