The median lethal pH (LpH50) was investigated for pH tolerance of Chinese Grass Shrimp (Palaemonetes sinensis) by the hydrostatic toxicity experiment method. The acidic range of pH was 3.0, 3.2, 3.4, 3.6, 3.8 and 4.0, and the alkaline range of pH was 10.4, 10.6, 10.8, 11.0, 11.2, and 11.4. The LpH50 in the acidic range was 3.416 for 24 h, 3.426 for 48 h, 3.463 for 72 h and 3.463 for 96 h, respectively (Table 2); The LpH50 in the alkaline range was 10.813 for 24 h, 10.609 for 48 h, 10.516 for 72 h and 10.516 for 96 h, respectively (Table 4). Security pH values were 4.463 and 9.516, respectively. Subsequently, the effects of pH on the oxygen consumption rate, ammonia excretion rate and asphyxiation point in P. sinensis were studied by hydrostatic test based on LpH50. The pH values were set to 4, 5, 6, 7, 8, 9, 10, and pH 7 was control group. We used the software SPSS 18.0 to analyze the experimental data. An analysis of variance (ANOVA) was used to analyze the experimental results, and Duncan was used for multiple comparisons. The results showed that oxygen consumption rates at pH 9 and 10 were significantly increased compared to the control pH (P < 0.05), and other pH groups did not have significantly change (P > 0.05) (Fig. 1); the ammonia excretion rates at pH 5 and 6 were significantly higher compared to the control pH (P < 0.05), and other pH groups did not have significantly change (P > 0.05) (Fig. 2); the range of oxygen-nitrogen ratio (O/N) in P. sinensis was 4.14 ~ 10.95 at pH 4﹣9, indicating that protein was the main energy supply material, however, O/N at pH 10 was sharply increased to 29.62 and the main energy supply material was fat instead of protein (Fig. 3). The asphyxiation point of P. sinensis had no significant difference among different pH groups (Fig. 4). The experimental results show that P. sinensis has strong tolerance to pH, but pH can affect respiratory metabolism and energy supply way in P. sinensis.