We designed and implemented a traffic analyze framework TraSt (Traffic Statistics) based on tcpdump for Android.This framework can get more detailed traffic usage than any other existing traffic monitor frameworks or applications on smart phones,and help us to explore four aspects of Chinese three major operators’ charging system as well as four kinds of popular smart phone applications.Our work helps 3G (the 3rd generation mobile telecommunication) users and software developers have a clearer understanding of the similarities and differences among the operators’ charging services,so as to promote the improvement of software development and operators’ services,and our analysis with recommendations to application developers can lead to better system design and network infrastructure support.