Martian soil simulants serve as substitute materials for authentic martian soil and have been widely employed in scientific research and engineering tests. The Martian Garden commercially supplies two martian soil simulants to global researchers: MMS-1 and the enhanced MMS-2. Although both have been utilized in numerous studies, critical essential data on their chemical and mineralogical compositions as well as spectral properties remain lacking, which limits the evaluation of material applicability and in-depth analysis of the related experimental results. In this study, we systematically characterized the chemical and mineralogical compositions as well as spectral properties of MMS-1 and MMS-2 using X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), electron probe microanalysis (EPMA), Fourier transform infrared spectroscopy (FTIR), visible-near infrared spectroscopy (VNIR), and scanning electron microscopy (SEM), followed by an evaluation of their applicability based on these results. The results indicate that the major chemical components of MMS-1 and MMS-2 (such as SiO₂, Al₂O₃, Fe₂O₃, MgO, and CaO) exhibit certain deviations from both the reference data provided by The Martian Garden and the chemical compositions of martian soils in situ measured at various landing sites. Nevertheless, they show a relatively high degree of similarity to the chemical compositions of soils or rocks at certain specific sampling points along the rover traverse paths. MMS-1 primarily consists of andesine, accompanied by minor pyroxene, Al-rich smectite, Mg-rich smectite, Fe(Ⅲ)-rich smectite, quartz, calcite, and hematite, along with trace amounts of gypsum, alunite, olivine, and amorphous silica, and possibly minor illite and indialite. Its VNIR spectrum closely matches observations from Mars orbiters on the global scale. MMS-2, built upon MMS-1, incorporates additional hematite, quartz, gypsum, and periclase, and possibly glauconite, with spectral features more consistent with the orbital data from localized gypsum-enriched areas on Mars. Overall, both MMS-1 and MMS-2 can be regarded as high-quality martian soil simulants. MMS-1 exhibits chemical composition, mineralogical assemblage, and spectral features that are highly similar to those of authentic martian soil, making it a suitable experimental material for scientific investigations related to Mars, including martian geological evolution. In contrast, MMS-2, as a simulant enriched in secondary minerals, confers distinct advantage for investigating the role of secondary minerals in martian soil amelioration. Following detailed characterization of their physical and mechanical properties, MMS-1 and MMS-2 are also applicable to rover engineering tests and in-situ resource utilization (ISRU) studies.