Effects of crumb rubber of different particle sizes (20mesh, 40mesh, 60mesh, 80mesh and120mesh) and contents (10%, 15% and 20% by weight of the total of CRM asphalt) on the properties of CRM asphalt and change rule of performance of CRM asphalt with reaction temperature and time were studied in laboratory. The results indicate that CRM asphalt has the best performance when the particle size of crumb rubber used is 80 mesh and the content is 15%. The performance of CRM asphalt is strongly depended on reaction temperature and time. When reaction temperature is higher than 200°C and time more than 60 minutes, the viscosity of CRM asphalt significantly decline with reaction temperature rising and time delaying. The performance of CRM asphalt starts aging when reaction time more than 4 hours at high temperature. Based on test results, some suggestions for production and application of CRM asphalt are put forward.