Abstract: A compound matrix composed of magnetic particles SmFeN (MPs) and sinapic acid (SA) was prepared and applied to the analysis of typical low-molecular mass peptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), leading to apparent enhancement of intensity of signals of MS peaks of the analytes. It was shown that the optimum mass ratio of SA to MPs in the compound matrix was 4:0.5, where under the intensity of analytical signal of SubP+Na⁺ was raised about 40 times. Furthermore, a brief discussion on the reaction mechanism of the compound matrix was given based on the results of study on the phenomena by UV-Vis diffuse reflectance spectroscopy.