OBJECTIVE： To compare the cost-effectiveness of cefazolin sodium pentahydrate versus cefazolin sodium in treatment of bacterial infection， and to provide reference for rational drug use in the clinic. METHODS： In retrospective study， 207 bacterial infection patients receiving cefazolin sodium pentahydrate or cefazolin sodium were selected from our hospital during Nov. 2014 to Dec. 2015， including 109 cases in cefazolin sodium pentahydrate group and 98 cases in cefazolin sodium group. Both groups received relevant medicine 2 g， bid， ivgtt， within 7 d. The clinical efficacies， bacteriological efficacies and safety of 2 groups were compared， and pharmacoeconomics of 2 therapy plans were evaluated. RESULTS： The clinical response rates of cefazolin sodium pentahydrate group and cefazolin sodium group were 89.91％ and 74.49％， with statistical significance （P＜0.05）； bacterial clearance rates were 76.32％ and 72.13％， with no statistical significance （P＞0.05）. No drug-related ADR occurred in 2 groups during the treatment. Total shot-term （7 d） cost of cefazolin sodium pentahydrate group and cefazolin sodium group respectively were 4 391.43 yuan and 3 396.19 yuan. Using clinical response rate as effect index， cost-effectiveness ratio of them were 48.84 and 45.59， and incremental cost-effectiveness ratio was 64.55， which was lower than per capita GDP of Hengshui city. The sensitivity analysis results were in agreement with the cost-effectiveness analysis. CONCLUSIONS： Under the current economic situation of Hengshui city， cefazolin sodium pentahydrate has cost-effectiveness advantage in the treatment of bacterial infection than cefazolin sodium.