The specific recognition and long-term continuously monitoring of antibiotics in water is extremely important for ecosystem and human health. Herein, we report a two-dimensional blue photoluminescence coordination polymer CdL·H2O (1) based on 9H-carbazole-2,7-dicarboxylic acid (H2L), emission of which could be significantly quenched only by aztreonam (ATM) among thirteen antibiotics in aqueous media. By the fluorescence titration experiments, the linear Stern-Volmer plot between emission intensities of 1 and ATM concentrations was observed in the concentration range of 20–100 μM with Ksv of 1.12×104 M−1. Besides high selectivity and sensitivity, good anti-interference ability and repeatability for ATM detection were also confirmed. In addition, we immersed 1 into the ATM solution for 60 days, and during this period the fluorescence quenching percentage of ATM for 1 almost unchanged. This result indicates that 1 could be used as a stable high-performance fluorescence sensing material for the specific recognition and long-term continuously monitoring of ATM in water. 1 is also the first fluorescent material that can detect ATM in water. The fluorescence quenching mechanism was attributed to photoinduced electron transfer (PET) from 1 to ATM.