In order to reduce the damage caused by slope height amplification effect in bench blasting in open pit mine , to reduce the error between the peak velocity v0 of the particle calculated v, based on the standard normal distribution, the peak value of blasting vibration velocity was approximately regarded as obey-normal distribution, the distribution function of random variable v was established, and the prediction formula of blasting vibration velocity was obtained by using the binary linear regression model in MATLAB, so as to evaluate the blasting vibration and safe explosive volume prediction of a certain open-pit mine bench slope. Finally, by comparing the engineering example with the modified Sadovsky formula, it is found that the maximum safety charge in a single section is reduced567 kg, which is more consistent with the actual situation, and the probability of protection of the target facilities is increased by 40.15%. The comparison results show that the evaluation of blasting vibration and the prediction of safety charge quantity by using the probability formula are obviously better than other methods.