In this study, the activated crumb rubbers (ACR) and these ACR modified asphalts were prepared. Effects of the preparation technology of modified asphalt and properties of activated crumb rubber on performance of modified asphalt have been investigated. The activated crumb rubber powder was characterized by the Rubber NMR Crosslink Density (RNCD). The mechanism of the activated crumb rubber modified asphalt (ACRMA) was analyzed by microcosmic measures and tests such as Fluorescence Microscope (FM) etc. The experimental results indicated that the chemical and physical activating methods can improve the swelling capacity of crumb rubber in the asphalt by destroying the three-dimensional network and decreasing the cross-linking density; ACRMA have better performance compared with the crumb rubber modified asphalt. Micrograph of the ACRMA demonstrated that the structure of ACRMA is more uniform and compact, and the performances of modified asphalt were improved significantly.