The paper based on the academic analyse of modified-asphalt's separate mechanics,tests diatomite,different content diatomite-modified-asphalt and different varieties diatomite-modified-asphalt by separate test and stereoscan.And it illuminates that difference of diatomite's quantity and microstructure will bring on the different asphalt's adsorbency,demonstrate the different consistency of diatomite-modified-asphalt,and gained the varied regularity of separation with time.The conclusion of this paper offers the academic gist for the actual application of diatomite-modified-asphalt.