Components of energy budgets of Pacific white shrimp( Penaeus vannamei ) juveniles with body length of 4. 5- 5. 0 cm fed on Limnodrilus sp. were measured at different water temperatures ( 20- 23 .. , 25 .. , 30 .. or 33 .. ) ) and salinities( 5, 15 or 25) by an experimental ecological method to improve husbandry for shrimp culture. The result s indicated that there were decrease in assimilation efficiency and increase in energy conversion efficiency with salinity increment within the range of 5- 25. At 5, there were the highest K1( 29. 02%) and the lowest assimilation eff iciency ( 77. 89% ) by the juveniles. The ef fect of salinity on assimilation eff iciency was dependent on respiration energy and compensative mechanism. There was an increase in specific growth rate ( y ) of the shrimp with water temperature ( X , .. ) increment as the fo llowing equation: y= 0. 0168lnX 0. 0831 ( R 2 = 0. 9324) . Better growth at high temperature is attributed to the high food consumption, high absorption and less feces. At the same water temperature, the shrimp has higher food consumption at fluctuated water temperature than at constant water temperature.