Abstract: Terrestrial impact by a near-Earth asteroid or comet occurs rare but may result in potentially catastrophic hazard.The researches on how to defense threat of near-Earth asteroids attract more and more attention. The paper summarizes the current situation of survey and detection of near-Earth asteroids and the major survey telescopes. And it also discusses the current state of assessing the potential impact risk and sequence in the recent researches. Finally, several proposed approaches that could prevent or mitigate the effects of potential impacting of near-Earth asteroids are analyzed and evaluated.