The current study primarily aims to develop a dictionary system for tracing mobile phone numbers for call centers of mobile communication companies. This system tries to save the numbers using a digital search tree in order to make the processes of searching and retrieving customers’ information easier and faster. Several shrubs that represent digits of the total phone numbers will be built through following the phone number digits to be added to the dictionary, with the owner name being at the last node in the tree. Thus, by such searching process, every phone number can be tracked digit-by-digit according to a required path inside its tree, until reaching the leaf. Then, the value stored in the node, that represents the name of phone number’s owner, is returned. Consequently, the amount of memory required to store data will be reduced and data retrieval will be faster.