Based on survey and biological data of butter fish collected in bottom trawl survey in continental shelf sea area located between north latitude 26.5 and 32.5 degree, outside of forbidden fishing line and up to depth 200 m area in the East China Sea, in the period from 2001 to 2005, growth and mortality parameters were estimated by using ELEFAN I technology based lengthfrequency data, von Bertalanffy growth equation was analogized, and we estimated the resource utilizing status of butter fish by BevertonHolt dynamic pool model. The results indicate that the growth parameters of von Bertalanffy growth equation is L_∞=267.8 mm；K=0.45 /a；t₀=-0.63 a. The growth process is not invariable. The growth at the young stage is very rapid. However, the growth rate decreases when a length of about 178.5 mm in fork length is reached. The age of growth inflection point is 1.81 a. Natural mortality coefficient (M) is 0.81 from Paluy equation and Zhan Bingyi linearity regression equation. Total mortality coefficient (Z) is 3.87, got from length converted catch curve with biology data by using the FiSAT，BevertonHolt dynamic pool model and CPUE. The fishing mortality coefficient (F) is equal to 3.06.According to the curve of equal catch using the BevertonHolt model, the present fishery point at F=3.06 and t_c=1.10 a locates inside of optimal yield section. The result of assessment indicates that the stock of butter fish has been exploited rationally at present and yield is close to maximum yield. Taking into account economic requirement and feasibility, this paper suggests that keeping the present fishing effort (F=3.06) and the fork length at first capture as 145 mm would get stable yields and protect stock of butter fish. The catch of butter fish kept steady and increased slowly in recent years although the commercial stocks of the East China Seahave been declined because the age of butter fish at the first capture is close to optimal age, i.e. the size of mesh is right to butter fish. So it can be used for reference in the management and protection of the main commercial stocks of the East China Sea.