The invention provides an aero-engine assembly task priority ordering method. The method includes the steps that firstly, according to a correlation dominance relation of task attributes, an attribute hierarchical model is established, indexes are quantitatively expressed, and after the attribute value of each task is processed, a standardized decision matrix is obtained; secondly, when index weights are determined, various weight calculation methods exist, on the basis, a multi-type weight balancing method with the minimum sum of the deviation square and the maximum sum of weighing index values serving as targets is raised, and therefore balance weights of the indexes are obtained; finally, the balance weights and the standardized decision matrix are used, the improved TOPSIS method with the Euclidean distance replaced by the contact distance is adopted for ordering row vectors in the weight standardized decision matrix, so that a priority order result of the tasks is obtained. According to the method, multiple types of weight information is comprehensively considered and balanced, information loss caused by single-type weight assignment can be reduced, and meanwhile, the improved TOPSIS method can overcome the defects of a traditional method.