Antimicrobial susceptibility test (AST) report was important for rational antimicrobial use. However, the reference value of AST report was sometimes limited due to poor information quality (IQ). This study aimed to measure the IQ of AST and evaluate the impact of IQ of AST report on rational antimicrobial use as a reference for antimicrobial therapy. The retrospective study included data of AST report, antimicrobials prescribed after reporting AST results and related inpatient information. The inclusion criteria of the AST report included three conditions: 1. The AST reports were from inpatients with diagnosis of infection. 2. The bacteria were extracted from a sterile-site specimen. 3. The interpretive categories (ie sensitive, intermediary or resistance) were firstly reported during one hospitalization. The IQ of AST report was measured by the total IQ and IQ of completeness, usefulness, accuracy and consistency. The rational antimicrobial use was measured by the antimicrobial adherence to the interpretive categories of AST report. Fractional logit regression model (FLRM) was chosen to evaluate the impact of IQ on the rational antimicrobial use. The median of the total IQ, completeness, usefulness, accuracy and consistency were 0.7345, 0.6082, 0.9167, 0.8966 and 1.0000, respectively. The results of FLRM showed that usefulness, accuracy and consistency had significant positive impacts on the rational antimicrobial use (β = 4.220, P < 0.001; β = 3.987, P < 0.001; β = 0.511, P = 0.001, respectively), while the total IQ and completeness had no statistically significant impacts on the rational antimicrobial use (β = -0.820, P = 0.35; β = -0.793, P = 0.20, respectively). This study confirmed that usefulness, accuracy and consistency performed well and had positive impacts on the rational antimicrobial use, which indicated that improving IQ especially usefulness, accuracy and consistency would make AST report play a greater role in promoting the rational antimicrobial use.