Abstract: Through the analysis with ESCA charts, it has proved that BET on the surface of Coal is absorbed by adding the BET as the increasing. The BET is not adsorbed basically on the surface of pyrite. The major difference between coal-pyrite and mineral-pyrite lies in their respective carbon spectroscopes. The peak intensity of coal-pyrite is obviously greater than that of mineral-pyrite. As seen in the form of the peaks, the irregularity of coal-pyrite is greater, showing that the existing form of carbonic materials in coal-pyrite is complex; whereas the carbon in mineral-pyrite exists mainly in the form of impurity carbon, and its surface content is about 30%. In terms of chemical computation composition, in minerals with carbon, its surface carbon content is more than 40%. There is no doubt that a high content of carbon plays a great part in the floatation of coal-pyrite. As a matter of fact, the carbonic pollution in the surface of pyrite and the incomplete isolation of coal and pyrite are one of the major reasons that coal and pyrite are hard to separate from each other. Through ultrasonic treatment, the absorption of Ca²⁺ on the surface of pyrite is further enhanced, and the Ca content increases form 0.95% to 2.95%. This proves that the desulfuration and deashing of coal through ultrasonic treatment is to enhance the absorption of Ca(OH)₂ on the surface of pyrite, and eventually to further depress pyrite.