Voltage dips (VDs) (including voltage momentary interruption) could cause interruptions of the producing processes, which brings significant economic loss to end-users. The evaluation of the economic loss of voltage dips provides a solid foundation for reasonable investments on power quality mitigation measures, and could be used by the end-users to make production plans. Few relative researches have been done so far in China. In order to get an evaluation model of plant-level economic loss due to voltage dips, this paper presents a detailed discussion in two dimensions, including the characteristics of a producing process interruption and the composition of cost during voltage dips. At last, an evaluation example is presented to testify this model, according to the results of one power quality economic survey in China. The calculation result presents a precise prediction of the plant-level lost caused by voltage dips for one single user.