In this paper, we analyzed the mineral properties, element composition and spectroscopy characteristics of orthopyroxene megacrysts in Heilongjiang Muling area via EPMA, Raman and FTIR analysis. The species, element composition and constitution water content of orthopyroxene megacrysts were determined. According to the EPMA results, we found that the orthopyroxene megacrysts in this area belong to orthopyroxene. The Raman spectra showed that the main bands of orthopyroxene megacrysts are 1 015, 678, 345 and 145 cm-1. The FTIR results showed that orthopyroxene megacrysts have three distinct peaks at 3 550～3 590, 3 510～3 520 and 3 410～3 420 cm-1. These absorption peaks are consistent with mantle derived pyroxene. The FTIR micro-region analysis showed that the constitution water is distributed unevenly in different orthopyroxene megacrysts but uniformly in the inner part one orthopyroxene megacryst, and there is no obvious change in the core-edge.