In view of the limited oil storage and the global warming threats, it has been a worldwide topic to build a low carbon society supported by sustainable energy. As an effective energy storage device for the sustainable energy, the lithium-ion battery has been attracting wide attention. Olivine LiFePO4 has been considered as the most promising cathode candidate for the next-generation large-scale lithium-ion battery used for hybrid electric vehicles (HEVs) or electric vehicles (EVs), because of its inherent merits including low toxicity, potential for low cost, long cycle ability and high safety. From 1997 to present, continuous efforts have been made to understand and improve the performance of LiFePO4. Now, it seems that olivine LiFePO4 is ready for its big time. In the present paper, we review the development of LiFePO4 in the past years, and discuss some remaining problems for LiFePO4 in the future based on our current study.