The process consists of: (1) digital holographic imaging for sensing marine plankton; (2) process of image of reconstructed image of marine plankton; (3) parameters measuring and extracting of marine plankton. The parameters measuring and extracting is a fundamental task in marine plankton sensing system and it is very important for study of marine plankton. The parameters can be served as input to some applications such as marine plankton tracking, identification and taxonomical classification, or other marine plankton study.