The invention provides a state evaluation method and device for a double-water internal cooling synchronous phase modifier cooling water system. the problem of real-time evaluation of the health states of the stator cooling water system and the rotor cooling water system of the double-water internal cooling synchronous motor is solved; The method comprises the steps of establishment of a stator cooling water system and a rotor cooling water system state evaluation index system, dimensionalization of evaluation indexes, classification of health state grades, determination of weights of the evaluation indexes and specific state evaluation. The dynamic weight of each index is determined in real time by adopting an entropy weight method, the similarity between the to-be-evaluated cloud and each standard cloud is determined based on the similar cloud, and the health state of the cooling water system is determined by adopting the maximum similarity principle. According to the invention, thereal health states of the stator cooling water system and the rotor cooling water system of the double-water internal cooling synchronous motor can be reflected, and the online state evaluation of thecooling water system can be realized.