Interpretation of fragment ions of complex samples such as bio samples and polymer mixed samples obtained with time-of-flight secondary ion mass spectrometry (TOF-SIMS) is often difficult because of overlapping of fragment ions. Molecular ions or large fragment ions in TOF-SIMS spectra are often hidden among strong peaks of secondary ions. Since G-SIMS, which has been developed to investigate secondary ions in detail, enhances molecular ions and more intact fragment ions, and therefore it is useful to interpret intricate sample spectra. In this study, G-SIMS was applied to a thin film of polyethylene (average molecular weight : 540-640) on Si substrate in order to investigate effectiveness of G-SIMS on polymer samples. As a result, G-SIMS spectra enhancing molecular ions and more intact fragment ions were obtained and indicate relationship between particular fragment ions, which is useful to interpret TOF-SIMS spectra.