Abstract: Temperature and salinity are two main factors affecting the metabolism of aquatic biological activity, and these environmental factors vary seasonally (e.g., high temperatures in summer and increased rainfall during the rainy season). This study investigated the effects of temperature and salinity on oxygen consumption rate and ammonia excretion of the zebra strain of the Manila clam Ruditapes philippinarum. The experimental conditions included a temperature gradient (15, 20, 25, 30, and 35℃) and a salinity gradient (20, 25, 30, 35, and 40). The results showed that temperature and salinity had a significant effect on oxygen consumption and ammonia excretion rates in this strain (P < 0.05). Higher temperature increased oxygen consumption and ammonia excretion. Oxygen consumption decreased first and then increased with increased salinity, whereas ammonia excretion increased first and then decreased. At 15℃, the O:N ratio ranged from 9.534 to 62.008 while salinity increased from 20 to 40. At salinity 35, the O:N ratio ranged from 20.700 to 74.138 while temperature increased from 15 to 35℃.