Breast cancer is a common and frequently-occurring disease which has serious impact on women's health and life. Aromatase inhibitors play an important role in endocrine treatment of breast cancer. It is necessary to find new aromatase inhibitors for the improvement of the treatment efficacy and the reduction of drug resistance and side effects. In this paper,490 molecules in Binding DB with the top aromatase activities (the lowest IC50 for aromatase inhibition) were disassembled into a few basic pieces to build molecular common structural fragment libraries of aromatase inhibitors using the RECAP analysis function module in MOE 2013 software. This library can provide basic molecular structural source materials for the new drug design of aromatase inhibitors.