A method of removing abnormal data in a blood component analysis system using spectroscopy to estimate a concentration of a blood component by analyzing a photo-plethysmographic (PPG) signal obtained by radiating light of first and second wavelengths reacting to the blood component on a subject and detecting light corresponding to the first and second wavelengths output from the subject, includes collecting the PPG signal corresponding to the first and second wavelengths for a predetermined unit period of time, calculating “n” parameters, with respect to “n” pulse data included in the collected PPG signal, where n is a positive integer, calculating an average of the “n” parameters, and comparing a ratio of a number of parameters whose deviation from the average is greater than a predetermined standard deviation to the “n” parameters with a predetermined removal reference value to determine whether the “n” pulse data is valid.