Shrimp has efficient non-specific defense mechanisms based on activities of the hemocytes against pathogens. Up to now, it has been known that one of the non-specific immune reactions is related to mutual association among types of hemocyte, granular cell, semi-granular cell, and hyaline cell. In this study, we tried to know the effectiveness of feed-additives such as 5-aminolevulinic acid(ALA), chitosan, and hot-water extract of herb on immunity of shrimp (Penaeus chinensis) by hemocytic observation and SDS-PAGE analysis. Finally, we suggest a principle of the examination system for effects of various feed-additives