Although trash fish is the major traditional diets for the current pond culture of swimming crab Portunus trituberculatus, feeding formulated diets are the future trend for the sustainable culture of P. trituberculatus. However, no available information could be found on the comparison of culture performance for feeding formulated diets and trash fish to pre-adult P. trituberculatus. By the individuals culture technique and biochemical analysis, this study was therefore conducted to investigate the effects of formualted diets (FD), trash fish (TF) and pig lung (PL) on the survival, molting, growth and biochemical composition of pre-adult P. trituberculatus (initial mean wet weight was around 70g). All statistical anlysis was performed using SPSS 17.0 software. Homogeneity of variance was tested by Levene’s test. When necessary, arcsine or square root were performed for the percentage data prior to analysis. An analysis of variance (ANOVA) was used to test for experimental data, and the Tukey s-b(K) test was used for multiple comparisons. The results are shown as the followings: (1) The diets had the significant effects on survival of pre-adult P. trituberculatus. FD treatment had the highest survival (90%) while the lowest survival (43%) was recorded in TF treatment (Table 3), and most of death was because of molting death syndrome (MDS). (2) FD treatment had the the shortest molting period, the highest percentage of crabs finished two molting during the culture experiment, the highest final body weight and specific growth rate (SGR) among the three treatments while the TF treatment had the lowest culture performance (Table 3). (3) Although FD treatment had the higher hepatopancreatic index than the other treatments, there was no significant difference among the three treatments (Table 3). (4) The diets had the significant effects on the proximate compositions of pre-adult P. trituberculatus (Table 3). The hepatopancreas and muscle of TF treatment had the lowest moisture content, but the highest contents of the other proximate compositions among the three treatments, while the contents of proximate compositions were similar for the other two treatments (Table 4). The fatty acid composition of hepatopancrea and muscle was significantly affected by the dietary fatty acids. TF treatment had the highest levels of highly unsaturated fatty acids while PL treatment had the highest levels of saturated fatty acids and mono- unsaturated fatty acids (Table 5,Table 6). Overall, TF treatment had the lowest relative retention rate of DHA(22:6n3) and EPA(20:5n3), but PL treatment had the highest relative retention rate of these two fatty acids (Table 7). In conclusion, the developed formualted diet could improve the culture performance for the pre-adult P. trituberculatus, which could be used to replace wildly used trash fish for a certain extent in the pond culture of P. trituberculatus.