Abstract: Ofloxacin residues in were determined using cylinder plate method, taking Micrococcus luteus 26003 as the test microorganism. Results showed that the detection limit of ofloxacin in faeces was 0.156μg/g, and the calibration curve was linear within the range of 0.156~5.00μg/g , the coefficients of variation for the microbiological method were 2.4%~3.3% in intra-assay and 3.7%~5.2% in inter-assay, the recoveries in faeces of chicken ranged from 79.49% to 87.92%.