Lens-free microscopic technology utilizes Gabor-based in-line holographic optical path to capture the interference images generated by illuminating lights through the micro-samples, with the help of an area array detector but without any imaging lenses. It is a digital microscopic imaging technology which uses a digital-picture-processing method to reconstruct image for the sake of acquiring information from these micro-samples. The shrinkage of equivalent pixel elements achieved by pixel super-resolution gives more high-frequency information and, further, it promotes the resolution of reconstruction directly. Meanwhile, multiple phase recovery arithmetic tools make the same contributions to resolution indirectly by eliminating the twin-images, especially to the dense samples. Moreover, such technology breaks the limitation in spatial bandwidth product, comparing to the classical optics microscopes, which leads to the high-resolution imaging in a larger field of view (FOV). Therefore, it can provide powerful supports for rapidly diagnosing samples with a big field of view in clinical application and examination in the case of resource shortage. Additionally, the booming algorithm with optimizing hardwares renders impetus in data-sampling and computing effects, expanding the applications on specimens moving in high speed and on a nanometer scale. The developing tendency of lens-free technology and its matched hard devices are to become compacted both arithmetically and volumetrically. Ultimately, the real-time, three dimensional, colorfully-imaging, portable and separated devices with high-resolution can be manufactured.