In order to better deal with the fuzziness of language and randomness of quantitative analysis of evaluation grade in blasting effect evaluation,a cloud model evaluation method for open-pit mine blasting effect was established based on DEMATEL-SEWM.DEMATEL(Decision Laboratory Analysis Method) and SEWM(Structural Entropy Weight Method) are used to calculate the weight coefficient of blasting effect evaluation indexes,which objectively reflects the influence of the correlation among indexes and the difference degree of index weight judgment.The randomness and fuzziness of blasting effect evaluation are objectively described by using cloud model eigenvalues,such as Expected Value Ex,Entropy 、En and Excess Entropy He.Considering the influence of various index weights,the comprehensive membership degree of blasting effect is analyzed and the evaluation grade of blasting effect of open-pit mine is determined according to the principle of maximum membership degree,so as to better realize the quantitative visual representation of fuzzy randomness of qualitative concept in blasting effect evaluation.The model was applied to evaluate the blasting effect of an open-pit mine,and the results showed that the mixed weights of each index are 0.101,0.102,0.154,0.163,0.128,0.112,0.132,0.107,respectively.According to the weight,it can be known that the powder factor,the big block percentage and the vibration velocity have a great influence on the blasting effect.The cause degree of the powder factor is 1.2961 and the cause degrees of other indicators are negative.Therefore,the powder factor is the reason element which is the key factor to improve the blasting effect.The comprehensive membership degrees of the four blasting effects are 0.358,0.339,0.360 and 0.469,respectively.Meanwhile,the evaluation grades of the four evaluation results are all above good,which are consistent with the actual situation and verified the effectiveness and feasibility of the model in blasting effect evaluation.