Abstract: Evaluating the hotspot degree of VM (virtual machine) is the critical step of the VM hotspot eliminating process. Traditional approaches of evaluating hotspot degree often monitor whether one or more threshold values being exceeded or not. The correlation among evaluation metrics and the adaptation of different metrics were not considered in the existing approaches for various services， which influences evaluation accuracy. The hotspot degree evaluation system is created， combining VM service availability and service quality factors. The subjective weight algorithm based on fuzzy analytic hierarchy process is proposed，as well as the objective weight algorithm based on maximum deviation and hotspot degree comprehensive evaluation method based on these two weights. A rule of VM coldspot or hotspot evaluation based on hotspot degree is presented. The experiment result indicates that the accuracy of the proposed method is higher than that of traditional approaches in evaluating the hotspot degree， which can efficiently reduce improper migration， with lower prices.

Key words: cloud computing, hotspot eliminating, VM hotspot degree, coldspot, fuzzy analytic hierarchy process