Kinetic research was carried out to compare the effects of storage temperature and lipid content on the rates of oxidative deterioration of lipid in fish muscles (skipjack, sardine) during storage at low temperatures (from 5 to -20°C). Peroxide value (POV) was preferable to other indexes for estimating lipid oxidation. Changes with time of POV in skipjack fillet and sardine minced muscles were plotted as sigmoid curves, and the oxidation rate of lipid was expressed as the apparent rate constant [h-1] of reaction obtained from the formula of the first-order auto-catalytic reaction. As a result, the effects of temperature, lipid content, and antioxidant on the rate of lipid oxidation were evaluated by the kinetic analysis. It appears reasonable to express the oxidative degree of lipid in the fish muscles using the corresponding amount of POV (POV-C), which was the amount of peroxide (meq/100g fish muscle) accumulated in the lipid content of 100g fish muscle, like a TBA number rather than the POV (meq/100g lipid).