The effect of salinity on muscle quality of the Sword Prawn (Parapenaeopsis hardwickii)was studied through testing the muscle nutrient composition, amino acid composition and content by culturing in different salinities. The results showed that the muscle moisture content significantly decreased, while the muscle protein content significantly increased with an increase in environment salinity from 12 to 36. No significant difference in muscle crude fat content was observed with salinity increase, although there was a slight decrease; The crude ash content at salinity 36 was significantly higher than that at salinity 12, 16, 20, 24 or 28. Among the 16 amino acids detected in the muscle, the content of 3 kinds significantly increased, while the content of other 13 kinds significantly decreased with an increase in salinity from 12 to 36; the content of 10 amino acids at salinity 12-24 was significantly higher than that at salinity 28-36, while no significant difference was detected from salinity 12 to24. No significant difference was found in total amino acid content or delicious amino acid content from salinity12 to 36. Both total essential amino acid content and total half-essential amino acid content at salinity 12-24 were significantly higher than those at salinity 28-36, while there was no significant difference from salinity 12 to 24 or from 28 to 36. Both the ratio of total essential amino acid to total amino acid and the ratio of total essential amino acid to total non-essential amino acid were significantly decreased with an increase in environment salinity from 12 to 36. The essential amino acid indexes (EAAI) at salinity 12-24(66.13-67.42)were higher than those at salinity 28-36(62.56-64.46). The results suggest that the optimal salinity range for muscle nutritive value is salinity 12-24, and that the Sword Prawn shows a low salinity trend. Considering the muscle moisture content and shrimp growth performance, the suitable salinity range for culture is salinity 16-24, and thus the Sword Prawn can potentially be cultured in the brackish water (16-24 salinity) existing in majority of the coastal areas.