The invention discloses an interactive multilevel decision method of a comprehensive evaluation in power quality based on a cloud model. By using the cloud model, fuzziness and randomness are integrated together to constitute a mapping between qualitative and quantitative factors, and as a basis of information expression, the feature tallies with fuzziness and randomness of power quality grades. Subjectivity and objectivity can be well unified by an improved interactive multilevel decision model. Through combination of subjectivity and objectivity, a new comprehensive evaluation method of power quality based on the cloud model and the interactive decision is formed to achieve a more accurate, more objective and more scientific evaluation conclusion.