Objective To evaluate the effects and the clinical significances of liquid resuscitation on blood gas analysis， acid-base balance， electrolytes， acute physiology and chronic health evaluationsⅡ（APACHEⅡ） score of patients with septic shock， and then to analyze the relations between serum chlorine （Cl－） level and APACHEⅡscore and the volume of liquid resuscitation. Methods According to the target of resuscitation （centre venous pressure 8-12mm Hg and mean arterial pressure≥65mm Hg）， 21 patients with septic shock received enough fluid for resuscitation during 24h . The results of blood gas analysis， acid-base balance， electrolytes， and APACHE Ⅱ score were compared between pre-resuscitation and 24h post-resuscitation by self-controlled prospective study. The relationships of the level of serum Cl－ and APACHEⅡ score with the volume of liquid used in resuscitation were analyzed . Results The mean resus-citation duration was （18.09±4.57） h， and the volume of liquid during 24 h resuscitation was 5 320-11 028mL with mean volume of （7 775±1 735） mL in 21 patients with septic shock. Serum sodium （Na＋， mmol/L） and Cl－（mmol/L）levels of post-resuscitation were significant higher than those of pre-resuscitation （Na＋：138.71±5.67 versus 135.62±7.23， P=0.024；Cl－：109.10±4.90 versus 101.67±8.59， P=0.000）. Compared with the levels of pre-resuscitation， the blood pH value， hematocrit （Hct，%）， anion gap （AG， mmol/L）， lactic acid （mmol/L）， and APACHE Ⅱscore significantly decreased （pH：7.31±0.05 versus 7.37±0.06， P=0.000；Hct：28.48±2.56 versus 32.76±9.19， P=0.049；AG：8.33±3.45 versus 14.17±8.83， P=0.004；lactic acid：1.66±0.89 versus 2.96±1.23， P=0.001；APACHEⅡ：10.90±3.73 versus 17.24±4.06， P=0.000） after 24h resuscitation. The correlation analysis showed that the level of serum Cl- was positively correlated with the volume of liquid used in resuscitation （r=0.717，P＜0.01）. However， there was no correlation between APACHEⅡscore and the volume of liquid used in resuscitation （P＞0.05）. Conclusions The target of liquid resuscitation in patients with septic shock should be cautiously determined， including control of the volume of crystal liquid for resuscitation， in order to avoid acid-base imbalance or hyperchloraemia. At the same time， the change in internal environment should be monitored. An optimistic fluid resuscitation to decrease APACHE Ⅱ score in patients with septic shock is unrelated to the volume of liquid resuscitation.