Micro-LED is emerging as new generation display technology due to their advantages of high efficiency, wide color gamut and long life. Although there are already many Micro LED based products and demons, the commercialization of Micro-LED technology still suffers from many technical challenges. In this short review paper, we describe the definition of Mirco-LED with a short summary of the milestones. From the perspective of the developments, we find that the integration process plays an important role in the fabricating Micro-LEDs. We then discuss the key fabrication processes of Micro LEDs with a focus on the technical challenges. In the end, a short perspective is also presented to discuss the future directions. Micro-LED display is still suffering from a number of technical challenges including mass transfer, full color technology, while the features of high resolution, fast response, low power consumption and long lifetime make them the most promising candidates for ultra-small and ultra-large displays demands, such as virtual/augmented reality and electronic billboards. These potebtial applications have motivated the exploration and investigation from both of academia and industry.