Objective To study the expression and clinical trend of procalcitonin (Pct) + lactate clearance in sepsis. Methods A total of 63 septic shock patients enrolled in our hospital from March 2018 to March 2021 were recruited as group A, and the 87 septic patients admitted during the same period were recruited as group B. The Pct, lactic acid, and lactate clearance were compared between the two groups. Results The Pct and lactic acid in group A were higher than those in group B at the time of diagnosis, 1 d, 2 d, and 3 d after treatment, but the lactate clearance rate at 1 d, 2 d, and 3 d after treatment was lower than that in group B (P < 0.05). The Pct and lactate at the time of diagnosis, 1 d, 2 d, and 3 d after treatment in the good prognosis group were lower than those in the poor prognosis group, but the lactate clearance rate at 1 d, 2 d, and 3 d after treatment was higher than that in the poor prognosis group (P < 0.05). Disease severity and prognosis were positively correlated with Pct and lactate, but negatively correlated with lactate clearance rate (P < 0.05). Conclusions Pct and lactate clearance rate might serve as accurate predictors of the severity of sepsis and prognosis. It merits promotion in clinical setting.