Abstract: Calcium sulfate whiskers (CSW) are an inorganic reinforcing material with promising application prospects. They have great potential for improving the performance of road materials. However, its strong polarity and hydrophilicity weaken its compatibility with organic materials such as asphalt and rubber powder, which limits its dispersion effect. In this study, a dopamine-like coating was constructed on the surface of CSW by the co-deposition of gallic acid (GA) and polyethyleneimine (PEI). An epoxy resin (ER) containing two epoxy groups was then grafted onto the coating to prepare phenol-amine-epoxy modified calcium sulfate whiskers (EMCSW). Subsequently, 4%~10% CSW or EMCSW and 25% activated crumb rubber (ACR) were added to the base asphalt to prepare CSW-ACRMA and EMCSW-ACRMA composite modified asphalt. SEM and FTIR analyses confirmed the successful formation of the coating on the CSW surface, significantly increasing its surface roughness and interfacial activity. The Brookfield rotational viscosity at 135℃ and softening point tests showed that, at an 8% dosage, the softening point and viscosity of EMCSW-ACRMA increased by 9.61% and 39.28%, respectively, compared with activated crumb rubber modified asphalt (ACRMA). The segregation test showed that, at an 8% dosage, the softening point difference of EMCSW-ACRMA decreased by 3.25℃ compared with that of CSW-ACRMA. The high-temperature rheological test results showed that EMCSW significantly improved the deformation resistance and high-temperature rutting resistance of ACRMA. The thermogravimetric results showed that EMCSW altered the thermal mass-loss behavior of ACRMA and enabled it to maintain relatively good thermal stability during the main thermal decomposition stage. Mechanism analysis showed that the organic coating on the whisker surface enhanced the interfacial interactions with crumb rubber and asphalt components, promoting the formation of a stable three-dimensional network and thereby improving the compatibility of the system. This study provides a feasible interfacial modification strategy for improving the high-temperature performance of ACRMA and further expands the application potential of CSW in asphalt modification systems.