Abstract: Due to the urgent needs in life sciences, the extended depth of field (EDOF) in microscopy is becoming a focus. In order to study the microscopy depth of filed, the EDOF was studied and summarized. Based on the dramatic enhancement of EDOF, the optical scanning, spatial light modulation, wavefront coding and light filed microscopy were introduced and compared synthetically. Their theory, method and capacities for EDOF were summarized, and the technology defect and future development were analyzed. With the enhancement of technologies, the depth of filed in microscopy can be enhanced about 1 or 2 orders of magnitude compared with traditional microscopy.