The changes in properties and structural parameters of four vacuum residue samples before and after ultrasonic treatment were analyzed.Ultrasonic treatment could increase the carbon residue value,decrease the average molecular weight and viscosity,which can barely influence the density of vacuum residue.Meanwhile the constitution of residue can be varied including the decrease in the content of saturates,aromatics and asphaltenes,while the increase in the content of resins can lead to an increase in the total content of asphaltenes and resins.Among the four kinds of residue samples,there is a common trend that the more the content of asphaltenes in feedstock is,the more the increase in the content of resins,the more significant decrease in the aromatic content and the less decrease in the saturates content after ultrasonic treatment of residue would be.Changes in the structure and content of asphaltenes caused by ultrasonic treatment have a significant impact on the changes in residue properties.Ultrasonic treatment has changed the structural parameters of residue such as decrease in the total carbon number of average molecule (CTotal),the total number of rings (RT),the aromatic carbon number (CA),the aromatic rings number (RA)and the naphthenic rings number (RN),and increase of characterization factor (KH).The study has indicated that ultrasonic treatment of vacuum residue can change the average structure of residue,and the changes in the content and structure of asphaltenes are the main cause leading to property changes.The results of residue hydrotreating revealed that coke yield decreased,whereas the gas and light oil yield and conversion increased after ultrasonic treatment of vacuum residue. The changes in properties and structural parameters of four vacuum residue samples before and after ultrasonic treatment were analyzed. Ultrasonic treatment could increase the carbon residue value, decrease the average molecular weight and viscosity, which can barely influence the density of vacuum residue. of residue can be varied including the decrease in the content of saturates, aromatics and asphaltenes, while the increase in the content of resins can lead to an increase in the total content of asphaltenes and resins. Among the four kinds of residue samples, there is a common trend that the more the content of asphaltenes in feedstock is, the more the increase in the content of resins, the more significant increase in the content of resins, the more significant decrease in the aromatic content and the less decrease in the saturates content after ultrasonic treatment of residue would be. Changes in the structure and content of asphaltenes caused by ultrasonic treatment have a significant impact on the changes in residue properties. Ultrasonic treatment has changed the structural parameters of the residue such as decrease in the total carbon number of average molecule (CTotal), the total number of rings (RT), the aromatic carbon number (CA) and the naphthenic rings number (RN), and increase of characterization factor (KH). The study has indicated that ultrasonic treatment of vacuum residue can change the average structure of residue, and the changes in content and structure of asphaltenes are the main cause leading to property changes. the results of residue hydrotreating revealed that coke yield decreased, the gas and light oil yield and conversion increased after ultrasonic treatment of vacuum residue.