The invention belongs to the field of electric power transaction, and particularly relates to a method for constructing a power transaction index system based on big data technology. The method mainlycomprises the following steps: 1, acquiring data; 2, constructing an index system: the construction of the index system is mainly based on a cloud gravity center evaluation method to solve the problem of variable conversion, and then data analysis is carried out through the high-concurrency distributed computing capability of the Spark memory access; 3, calculating indexes: after the index configuration, the weight of each index is determined through an objective weighting method, and then the weighted deviation degree of each index is calculated through a cloud gravity center evaluation method; and after the Spark calculation, the final evaluation result of each index is stored into the HDFS database; and 4, displaying the indexes. The constructed index system is a comprehensive system composed of a series of mutually linked indexes, and the conditions of various aspects of the research object can be effectively reflected according to the research object.