Method and apparatus for distinguishing radionuclide by using plastic scintillator

A method and an apparatus for distinguishing a radionuclide are disclosed. The method comprises the steps of: receiving energy generated from one or more radioactive elements; applying weighted values, which correspond to respective energies, to each channel of the received energy spectrum; and distinguishing the one or more radioactive elements on the basis of the energy spectrum to which weighted values were applied. A radioactive element having, as an energy value of the Compton edge, an energy value corresponding to the peak value of the energy spectrum to which weighted value is applied is determined to be the one or more radioactive elements. According to the present invention, radiation can be more accurately monitored while using a plastic scintillator and, further, the energy resolution of the plastic scintillator can be increased.