Abstract: The combustion synthesis reaction with reductive process was used to produce ZrB₂ / Al₂O₃ compositepowders f rom B₂O₃-ZrO2-Al system. The phases , chemical compositions and interfaces of the composite powderswere characterized and analysed by X-ray diff raction (XRD) , X-ray photoelect ron spect roscope (XPS) , t ransmissionelect ron microscope ( TEM) and high resolution elect ron microscope ( HRTEM) . The result s show that Zr , B , Aland O element s exist in composite powders as ZrB₂ and Al₂O₃ . The ZrB₂ and Al₂O₃ are the primary phase in thecomposite powders. The presence of a very small amount of ZrO2 is considered to be unreacted zirconium oxide powders. TEM and HRTEM observations of interface of the composite powders indicate that the good interfacial bonding states are formed between the ZrB₂ and Al₂O₃particle. It can be suggested to be related to the crystallizationprocess of the ZrB₂ particles.