Abstract: An ultra-short ultra-intense laser can excite high-amplitude electron plasma waves or so called laser wakefields when it propagates in under-dense gas plasma. A laser wakefield accelerator makes use of such waves to accelerate charged particles (especially electrons and positrons). These plasma waves can sustain longitudinal acceleration fields over three orders of magnitude higher than conventional radio frequency accelerators. This new type of laser-driven plasma-based accelerator opens the way for compact particle accelerators and radiation sources. It also has the potential to be applied for the construction of future ultra-high energy TeV electron-positron colliders and free electron lasers. In this paper, the principle, characteristics and development history of this new accelerator, especially the main progress in the past ten years, the future development trend and the main challenges will be briefly reviewed and introduced.