The invention discloses a power grid index data processing method which is executed in a calculation device and is applicable to grading processing of index data, wherein the index data is power grid index data. The power grid index data processing method comprises steps of obtaining an index data sequence, wherein the index data sequence comprises multiple index data, calculating the average value and the standard deviation of the index data sequence and calculating the ratio of the standard deviation and the average value to obtain a variable coefficient of the index data sequence, determining the distribution type of the sequence data according to the variation coefficient of the index data sequence, wherein the distribution type comprises an intensive type, a middle type and a discrete type, determining a grading processing algorithm according to the distribution type of the index data, and performing grading processing on the index data according to the determined grading processing algorithm. The invention discloses a corresponding power grid data processing device and a calculation device comprising the power grid index data processing device.