In this work , we will show a way to distinguish various kinds of light nuclear isotops in cosmic-rays using boosted decision tree. Magnetic spectrometers are typically equipped with a magnet, a tracking system and a time-of-flight. This combination of apparatus can be used to reconstruct mass information of incoming charged particles from measurements of rigidity, speed and charge so that we can identify the incoming particles by their masses. A multivariate approach is found to be helpful to determine the separation power of particle identification among light isotopes.