Public transport, especially the bus transport, has been well developed in most cities. Thus the technique of bus arrival time prediction has become a research hotspot nowadays. It is a very important subject to improve the precision and reliability of the bus arrival time prediction, reduce travelers anxieties and waiting times at bus stop. In this paper, we propose EasyComeEasyGo(ECEG), a novel bus arrival time prediction system based on smart phone for passengers who are traveling with bus in real-life scenarios. This study presents an algorithm that uses real-time GPS data from field and takes delays automatically into account for an accurate prediction of bus arrival time. We develop a prototype system with different types of android-based smart phone and actual GPS data from bus route 26 located in Dalian, China are used as a test bed. We have extensively evaluated the ECEG system with the bus route 26 over a month period. Our results suggest that the proposed system achieves outstanding prediction accuracy and gains most travelers satisfy.