Acidified montmorillonite ( HMMT) was modified with isophorone diisocyanate ( IPDI) ,and the obtained IPDI-HMMT was used as a chemical modifier to modify asphalt via melt blending.Then,the physical properties,UV aging resistance and thermal stability of the modified asphalt were investigated.The results show that ( 1) IPDI-HMMT grafted with —NCO can react with the hydroxy in asphalt to produce urethane and to form an exfoliated structure; ( 2) after the incorporation of IPDI-HMMT,the initial decomposition temperature of the modified asphalt increases by 9℃,the softening point is up to 57.0℃,and the segregation softening point difference,the mass change rate,the softening point increment and the residual penetration ratio all change more slightly than those of Na-MMT modified asphalt; and ( 3) the chemical reaction between IPDI-HMMT and asphalt enhances the interaction of the internal components,which helps to form a stable colloidal structure,so that IPDI-HMMT has greater enhancement effect on the asphalt performance than Na-MMT.