The biochemical composition of one-year old ( weight: 40- 80g) and two-year old Fugu obscurus ( weight: 200- 300g ) cultured in ponds was studied. The results showed the content of crude protein of twoyear old f ish was lower than that of one-year old, but the content of crude fat is higher than that of one-year old obviously. Among essential amino acids, the level of lysine and arginine of two-year old f ish were apparently higher than that of one-year old, the contents of the other amino acids are all lower than those of one-year old, and their component rates were similar. Among non-essential amino acids, glutamic acid content is the highest in both one-year and two-year old fish, which is 26. 54% and 26. 69% respectively. The contents of monounsaturated fatty acids of two-year old fish are higher than those of one-year old, especially the C18B1which content of two-year old fish increased by 12. 23% . But the contents of saturated and highunsaturated fatty acids of one-year old f ish are higher than those of two-year old, especially the DHA which contents are 12. 86%, 8. 43% respect ively. Among the 14 measured mineral elements, the contents of Ca、Zn of two-year old f ish are obviously higher than those of one-year old, the contents of the other elements are lower than or almost close to those of one-year old f ish.