Abstract: The dietary test of shrimp, P. orientalis, was designed by meansof the gradient menthod for linoleic acid and linolenic acid. The results showedthat percentage weight gain and survival rate of the shrimp were affected by bothcontent and ratio of linoleic acid and linolenic acid. In the present test the opti-mal requirement of slirimp for linoleic acid and linolenic acid in the diet respe-etively was 2.16% and 0.87%, the optimal ratio of them was 2.48, and the linoleicacid as an essential fatty acid is more effective than linoleic acid. In the shrimppractical diet containing lots of plant protein feedstuff rich in linoleic acid, theoptimal percentage weight gain and survival rate of shrimp can be got by addingsome level of linoleic acid and linolenic acid as there were the higher ratio andlower content of linoleic acid and linolenic acid in the diet.