Laser feedback confocal tomography was used for high-resolution surface topography measurement, internal imaging of MEMS devices due to its extremely high sensitivity and longitudinal resolution, and can locate metal foreign objects in biological tissues. However, so far no cell-level imaging of biological tissues has ever been performed. A three-dimensional imaging system based on laser feedback confocal tomography was designed and built. The living tissue was detected and reconstructed, and the structure information of the cells can be clearly observed, which can prove its application value and development potential of technology in the field of biological tissue imaging. The three-dimensional imaging system can obtain a lateral resolution of 1.4 times the diffraction limit. When a microscope objective lens with $NA = 0.42$ was used, the lateral resolution was about 1.1 microns and the longitudinal resolution was 19.4 μm. It was used for surface topography measurement better than 500 nm.At the same time, a 3D positioning and scanning acquisition module based on LabVIEW software and a 3D image reconstruction module based on Matlab software were designed to accurately locate the area to be measured, and then obtain a 3D tomographic image of the area to be measured, which has considerable practical application value.