Abstract: OBJECTIVE To investigate the value of procalcitonin (PCT), lactic acid and C reactive protein (CRP) in septic shock and its prognostic value. METHODS A total of 153 cases of patients with septic shock were selected from the hospital from Jan. 2012 to Jan. 2017. According to the prognosis, 107 cases of patients transferred out of ICU/EICU were set as survival group, and 46 cases of death patients were set as death group. The peripheral blood samples were extracted, and the serum was separated. The immunoassay method was used to detect PCT, the dry chemical method was used to detect lactic acid, and the enzyme rate turbidimetry was used to detect CRP. The acute physiology and chronic health score (APACHE II score) and white blood cell count (WBC) at the time of admissionin, and the levels of PCT, lactate and CRP at 1, 3, 5d after admission were observed and analyzed. RESULTS At the time of admission, the APACHE Ⅱ score and WBC level of survival group were (18.49±3.46) points and (10.89±1.68)×10⁹/L, which were lower than those of death group (P<0.05). At 1, 3, 5d after admission, the leves of PCT, lactic acid and CRP of survival group were lower than those of death group (P<0.05). There were significant differences in the levels of PCT, lactic acid and CRP in survival group (P<0.05). There were significant differences in the levels of PCT, lactic acid and CRP in death group (P<0.05). CONCLUSION PCT, lactic acid and CRP play an important role in the evaluation of prognosis in patients with septic shock.