Objective To evaluate the effects and safety of procalcitonin(PCT)-guided algorithms of antibiotic therapy in critically ill patients in intensive care unit (ICU). Methods Literatures in English and Chinese concerning randomized controlled trials(RCTs) on PCT-guided algorithms of antibiotic therapy in critically ill patients was retrieved by electronic and manual search. All related data were extracted. Meta-analysis was conducted using the statistical software RevMan 5.3 on the basis of strict quality evaluation. Results Eight RCTs involving 2708 ICU patients were included, with 1360 patients in the PCT-guided group and 1348 patients in the control group. Compared with the control group, PCT-guided algorithms were associated with a significant reduction in the duration of antibiotic therapy (MD -2.44 days, 95%CI -3.25 to -1.62, P < 0.00001), and the occurrence of adverse reaction of antibiotics was also lower (RR=0.74, 95%CI 0.56 to 0.97, P=0.03), however the mortality exhibited no difference between the PCT-guided group and the control group (RR=1.00, 95%CI 0.89 to 1.13, P=0.99). Conclusion PCT-guided algorithms can shorten the duration of antibiotic therapy and reduce the occurrence of adverse reaction in critically ill patients without significant effect on mortality.