Crustaceans (including shrimp and crab, hereinafter), mollusks are important components of China's diversified food supply system and a major source of high-quality animal protein. In order to scientifically calculate the edible portion of crustaceans and mollusks, enhance the practicality of fisheries statistical data, and achieve rapid conversion between shell weight and edible weight of aquatic products, the National Fisheries Extension Service and the Chinese Fisheries Society organized a study in 2022 on the conversion coefficients of meat yield and shell weight of crustaceans and mollusks. This study formulated feasible technical routes, clarified unified definitions, measurement, and calculation methods, conducted weighing and measurement of crustaceans and mollusks of different sizes and varieties in different regions, and used SPSS 22.0 software for data processing. The study provided calculation results of meat yield, shell weight, and conversion coefficients for all crustacean and mollusk species included in the China Fisheries Statistical Yearbook, analyzing the impact of size, gender, and region on meat yield differences. Results showed that average meat yield for shrimp ranged from 0.118 to 0.546, crabs ranged from 0.305 to 0.680, and mollusks ranged from 0.232 to 0.732. Significant differences in meat yield were found only among different sizes of Litopenaeus vannamei and Procambarus clarkii, while no significant differences were observed among different sizes of other shrimp and crab species. Additionally, besides Charybdis japonica, significant differences in meat yield between females and males were observed in species such as Portunus trituberculatus, Scylla paramamosain, and Eriocheir sinensis, with females generally having higher meat yields than males. The study also proposed concepts and statistical methods for edible portions of crustaceans and mollusks, and calculated the edible portions of crustaceans and mollusks in China for the years 2020 and 2022. The results and conclusions of this study can provide reference for government departments in formulating policies and making decisions, and can also serve as a reference for relevant units in analyzing the dietary nutrition structure and actual intake of animal protein by Chinese residents.