Microorganisms, such as bacteria, are always detection objects in point-of-care testing, such as infectious diseases diagnosis, food safety monitoring and environment pollution detection. Optical microscopy is always a tool which is used to detect and analyze these detection objects. Lensless microscopy combines the sample with photodetectors such as charge coupled device (CCD) or complementary metal-oxide semiconductor (CMOS). This technique does not need optical devices, and the samples are imaged directly. The device is significantly simpler, smaller, easier to manipulate and cheaper than that of lens-based conventional microscope, which has been used in microstructure examinations, cell morphological analysis and microorganism detection. The lensless microscopic technology can be divided into three types, such as shadow imaging, fluorescence imaging and digital inline holography according to imaging principle. This paper reviews imaging principle and physical structure of three kinds of lensless microscopic technologies, and summaries the applications of lensless microscopic technologies in point-of-care testing. At last, we discuss the future development of lensless microscopic technologies.