Particle size distribution (PSD) is a key feature of mineral fractions in soils and sediments. It directly affects many physical and mechanical properties that are closely related to the geological origin and evolution of soils and sediments. However, precise PSD measurement is still unrealized, especially for fine and precious samples such as lunar soils which require a noninvasive and nondestructive methodology. In this study, using Laser Diffraction Particle Size (LDPS) analysis as a reference, we compared PSD results of lunar soil simulants measured using three-dimensional X-ray Microscopy (XRM), Optical Microscopy (OM), and Scanning Electron Microscopy (SEM) approaches. Our experimental results showed that the PSD (in numbers) measured by the different methods was not consistent, whereas the PSD (in volume/area) showed some consistency, at least within a certain size range. Comparatively, (i) SEM reliably measured particles in the range of ~0.1-10 μm, (ii) OM was effective for particles with sizes ranging from ~10 to 75 μm, and (iii) XRM effectively measured those particles with sizes ranging from a few microns to a few hundred microns and showed relatively positive consistency with the LDPS result especially for particles above ~75 μm. By employing the Boltzmann model to integrate the particle size accumulation (PSA) data from different measurement methods, we propose a multi-approach method for the precise determination of particle size. This method can be applied for the particle size analysis of soils or regoliths returned from the Moon or other extraterrestrial objects.