Abstract: In order to provide the basic data for kinematic and dynamic analysis of pretreatment process of silver carp (hypophthalmichthys molitrix), the distribution law of mass and sectional area of silver carp along the length direction was researched. Silver carps with mass between 800 g and 1050 g were taken as the research objects. The mass distribution regression model along the length direction was obtained by slicing-weighing technology, and the sectional area distribution regression model was obtained by digital image processing technology. The results showed that both mass and sectional area models of silver carps significantly represented cubic polynomial distribution characteristic (P<0.01). The mean relative error of predict value of mass and sectional area was 8.06% and 4.60%. The results of this study showed that the models can characterize the mass and sectional area of silver carps.