Zhenyuan gold deposit belongs to fine disseminated gold deposits located in Ailao Mountain.This type of gold ore is often associated with sulfide and carbon，which could diminish the gold cyanidation leaching efficiency and reduce the gold recovery efficiency in the next step.In order to guarantee the recovery rate of gold,the process mineralogy has to be proceeded to ensure the gold wasn’t been wasted due to the improper process.X-ray diffraction，X-ray fluorescence，Energy Dispersive X-Ray Spectroscopy，particle size test and mineral liberation analysis have been used to determine the chemical composition，mineral composition，particle size and the characteristic of Zhenyuan refractory gold ore obtained from Zhenyuan gold deposit.The X-ray diffraction，X-ray fluorescence，Energy Dispersive X-Ray Spectroscopy and mineral liberation analysis（MLA） shows that the main phase of the concentrate is sulfide（32.37% of pyrite，0.58% of stibnite and 0.46% of arsenopyrite），carbonate，silicate and the chemical component of concentrate is mainly iron（10.86%），sulfur（12.48%），silicon（18.56%）.Meanwhile 0.87% of arsenic and 5.55% of carbon（3.18% organic carbon and 2.37% inorganic carbon） have been found from the sample，which is harmful to cyanidation process. The particle size，encapsulation and exposure of pyrite，stibnite and arsenopyrite were analyzed with particle size test and MLA test. The particle size of sulfide is mainly between 10~75 μm，about 90%.A large number of sulfide is fully encapsulated（83.6%），only few of them are totally covered with gangue（0.9%）.Gold diagnostic leaching and MLA test were carried out to determine the occurrence state of gold.Sodium cyanide，acetonitrile，nitric acid and fire-assaying method has been used to determine the gold chemical content in native gold，sulfide，carbon and silicate.The gold diagnostic leaching result shows that 96.16% of gold is covered with sulfide and few is in the form of native gold or covered with silicate and carbonate.No gold is wrapped in carbon.MLA test could automatically diagnose different phase of gold ore based on electron software，energy spectrum and MLA software.It also could built standard data base of sample ore and calculate the process mineralogy data automatically.From the MLA test，the electron microscopy （SEM） images of sulfide and native gold has been collected and analyzed，which shows the similar result with gold diagnostic test that most of the gold is wrapped in sulfide. According to the mineralogy process which have proceeded，this gold concentrate is a carbon-baring sulfide gold ore.Since most of the gold is fully covered with sulfide，the sulfide removing process is becoming necessary.It is recommended that oxidation or grinding process should be proceeded before gold leaching process.