Abstract: The oily luster of nephrite is an important standard of evaluating quality of nephrite.The definition of oily luster of nephrite is very important for evaluating nephrite quality and standardizing nephrite market.The authors used market survey method, factory-processing testing and instrument (UV-Visible spectrometer, gloss meter, comprehensive measurement system for surface profile) to make a systematical research on oily luster of nephrite.Conclusion as follows:(1) The market questionaire survey shows that most respondents believe oily luster mainly includes the greasy luster, a fine structure and polishing; (2) Polishing experiments show the same samples with different polishing degree show different oily luster; even with the same polishing degree, samples with different structure also show different oily luster; (3) The gloss meter, UV-Visible spectra and comprehensive measurement system for surface profile show that polishing degree can affect the surface gloss, reflectance and roughness of nephrite.In the end, definition of oily luster includes two parts:One is nephrite exquisite and uniform structure that producing light dispersion effect, and the other is when nephrite given appropriate polishing, the greasy luster can emerge.