The Chinese prawn embryos in several developing stages are exposed to vcarious cryoprotective agents (CPA) brine solutions for toxicity and permeability study. CPA toxicity experiment shows that the embryos in gastrula or later stages can be more viable when surviving in GPA brine, DMSO is more suitable than glycerol as cryoprotective agents. Digital image processing technology is used to obtain the embryo volume changes during precryoprotection handling process, and a complicated CPA permeation model for embryos with two membrane is developed to analyse the experimental data. The results show that water can permeate the primary membrane of the Chinese prawn embryo, but DMSO and glycerol can not.