In order to find the best liquid nitrogen cryogenic freezing condition to maintain the quality of swimming crab(Portunus trituberculatus), the physicochemical properties of the samples, such as pH, thiobarbituric acid (TBA), total volatile base nitrogen (TVB-N), salt soluble protein content and total sulfydryl were determined to compare the quality of the swimming crab meat after different process.The swimming carb was frozen to center temperature of -25, -35, -45, -55℃ with the cooling rate of 2min down to -90℃, 5min down to -90℃ and 2min down to -70℃, respectively. The frozen carbs were stored at -20, -35, -40℃. The results showed that with the decrease of the central temperature and the freezing rate, the total sulfydryl and salt soluble protein content increased gradually while the TBA and TVB-N values decreased gradually. The TVB-N value of the samples with the center temperature of -25℃ was 15.85mg/100g and the sample frozen to -55℃ was only 12.99 mg/100g. The TVB-N and TBA values of the samples stored under -35℃ were lower than those stored at -20℃ and -40℃. The above results indicated that frozen by liquid nitrogen cryogenic freezing within 2min to -90℃ with center point of -55℃ and stored at -35℃ was the best for the swimming carb.