The invention discloses a method and system for determining stability of electric communication business performance indexes. The method comprises the following steps of: making a business index system according to a business stability index selection principle under an electric communication transmission network environment; determining a weight value of each index in the business index system through comprehensively utilizing a fuzzy analytical hierarchy process and an entropy weight method; carrying out dimensionless processing on an index value of each index in the business index system soas to calculate an exponent of each index; and calculating a stability comprehensive exponent by utilizing a comprehensive exponent calculation formula according to the weight value and exponent of each index in the business index system. According to the method and system, a fuzzy analytical hierarchy process and entropy weight method combined method is used for determining the weight values ofthe indexes, so that the relative importance degree of each index can be really reflected, advantages of the two methods can be sufficiently utilized and influences of subjective and objective factorsare avoided; and the method and system can be applied in a whole wide area stability control system so that technical reference is provided for the stability evaluation of a whole wide area stabilitybusiness.