Color is one of the important optical properties of gemstones, and it is also an important parameter affecting their quality and price. As a common jade variety, the complex structure, color ions, valence states and coordination of yellow-green prehnite have led to great controversy about its color genesis. In this paper, the species, valence, and coordination state of the main chromogenic ions of two typical yellow-green prehnite samples (light yellow-green sample LYG and dark yellow-green sample DYG) were investigated using modern analytical methods such as Fourier infrared absorption spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), laser-exfoliation-plasma mass spectrometry (LA-ICP-MS) and Mssbauer spectroscopy, which provides a scientific explanation for the color genesis of yellow-green prehnite. UV-Vis analysis indicates that both sample LYG and sample DYG showed obvious absorption bands at ~425 and ~585 nm, which were related to the electron leap of Fe3+oct and the charge transfer of Fe2+ch-Fe3+oct, respectively. Ultrafine parameter analysis of Mssbauer shows that the IS of Fe3+ in both sample LYG and sample DYG is 0.34 mm·s-1, and the QS values are 0.22 and 0.35 mm·s-1, respectively, both consistent with the characterization of Fe3+ in the octahedral ligand of prehnite. Sample LYG (IS=1.08 mm·s-1) and sample DYG (IS=1.07 mm·s-1) have similar IS values for Fe2+, both of which are consistent with the characterization of Fe2+ in octahedral coordination. However, the QS value of Fe3+ in sample DYG (QS=2.78 mm·s-1) is significantly higher than that of the light yellow-green sample LYG (QS=1.12 mm·s-1), suggesting that Fe2+ is in the distorted octahedron in the former structure. The content of Fe and the proportion of Fe2+ in sample DYG (4.04 wt%; 11.88%) are higher than those of the light yellow-green sample LYG (3.55 wt%; 5.27%), suggesting that the yellow-green color of prehnite may be related to the content of Fe and the proportion of Fe2+. The contents of V in sample LYG and the dark yellow-green sample DYG are 633 and 1 810 μg·g-1, respectively, indicating that V may contribute to the yellow-green color of prehnite. Still, its content is significantly lower than Fe, so the contribution to the color is much lower than Fe3+ and Fe2+. The present study not only identified the main chromogenic ion species (Fe) of yellow-green prehnite, but also determined the valence states (Fe3+ and Fe2+) and coordination states (octahedral coordination) of the chromogenic ions, which provides a solid theoretical basis for the quantitative study of the color of yellow-green prehnite.