Abstract: There are tiny content of fine-grained minerals like monazite and zircon in metamorphic rocks and they can be hardly tested by polarized reflecting microscope identification technology and X-ray diffraction analysis. With the SEM-EDS analysis technology, the main mineral components and element concentration can be determined. With the Casino and Quanta programs, the mass fraction (%) of each element can be calculated based on the element concentration. This study tests the trace minerals of 6 samples by SEM-EDS. The result shows that the main elements are composed of O, Ce, Nd, La, Al, P, Ca, Si, Ag and Th, which is consistent with the composition of monazite. Thus it can be concluded that the 6 samples belong to monazite.