According to one embodiment of the present invention, a data similarity evaluation system simplifying a calculation method of similarity evaluation comprises: a collection unit for collecting data a processing unit for comparing the data collected through the collection unit and a display unit for displaying a comparison result from the processing unit. The processing unit can calculate a rate of change which is a ratio of a first change amount and a second change amount, wherein the first change amount is a difference between a value at one point of the data and a reference value and the second change amount is a difference between a value at the same point of another data and the reference value. The processing unit can calculate similarity between the data as the maximum value when the rate of change is 1, calculate the similarity as the minimum value when the rate of change is -1, and calculate the similarity to 0 when the rate of change is 0 and when the rate of change is infinitely divergent.COPYRIGHT KIPO 2018
