Abstract: To enhance the scientific rigor and accuracy of reactor condition assessment, this paper proposes a novel evaluation model based on game theory combined weighting and an improved TOPSlS method. First, the subjective and objective weights of evaluation indicators are calculated using the analytic hierarchy process(AHP) and the entropy weight method, respectively. These weights are then optimized and integrated using game theory to construct a more rational weighting scheme. Then, the cloud model theory is introduced to quantify the correlation of each state indicator based on reactor operation data, thereby establishing a decision matrix. Finally, the improved TOPSlS method is employed to calculate the relative closeness of various states, enabling a comprehensive evaluation of the reactor′s operational health. Through a case study, the proposed method is validated to effectively reflect the actual operating conditions of reactors, providing a reliable basis for operation and maintenance strategies.