Based on the theoretical analysis,the frequency domain expression of equivalent blast load of group holes is derived,which is substituted into the expression of amplitude spectrum of blasting vibration velocity in cohesive rock mass.The expression of amplitude spectrum of rock mass vibration velocity excited by simultaneous blasting of group holes is obtained.As to open-pit bench deep hole blasting,four hole blasting with square layout is taken as the research object.The influence factors of rock mass vibration frequency and attenuation mechanism of main frequency are studied.The results show that with the increase of blast center distance,blast hole spacing and single hole charge,the frequency spectrum structure shifts from high frequency to low frequency,at the same time the increase of pitch or blast hole spacing blasting,blasting vibration main frequency attenuation obviously,and the rise time and fall time of explosion load directly influence the proportion of blasting vibration spectrum.Comparing the attenuation law of the main frequency of blasting vibration under three typical rock parameters,it is found that the main frequency is in direct proportion to the elastic modulus of rock mass and the longitudinal wave velocity,while the attenuation speed of the main frequency is inversely proportional to the elastic modulus and longitudinal wave velocity of the rock mass.The vibration frequency excited by blasting in Jinping marble is relatively small,and the main frequency attenuation speed is the fastest.