The stydy was carried out to investigate and review the principles and practices of immunocytochemical method in light microscopic level. The results were as follows. 1. Immunocytochemistry is the method to search out the intracellular position of the specific meterials using antigen-antibody reaction, 2. The chief items in immunocytochemistry are antigen, antibody and chromogen. 3. The identifical fixation is cardiac perfusion fixation. 4. The tissue slides must be prepared by vibratomy. 5. All stainings are carried out with free floating staining method. 6. There are polyclonal and monoclonal antibodies used in immunocytochemistry.