Abstract: The aims are to improve the growth condition of fenpropathrin-degrading bacteria in the growth medium, explore the basal salt medium formula and provide the basis for mass propagation of fenpropathrindegrading bacteria. In this paper, a strain of degrading bacteria (Y1) was preconcentrated and screened from the sludge and then preserved, which was identified as Bacillus cereus. OD600 was measured through the singlefactor test, and the optimal carbon and nitrogen sources were determined. The optimal basal salt culture medium was obtained through the orthogonal test. The results showed that optimal carbon and nitrogen sources were sucrose and peptone, and the optimal concentrations were 0.15% and 2.5%. The best basal salt medium was pH 6.0, sucrose 0.15%, peptone 2.5%, K2HPO4 0.001%, KH2PO4 0.01%, MgSO4·7H2O 0.1%，NaCl 0.01%. Y1 could multiply in the optimized basal salt medium, which established the foundation of its remediation for soil contaminated by fenpropathrin.