Aiming at the problem of 1, 1, 1-trichloroethane pollution in groundwater, a nano-zero valent iron-polylactic acid-biochar composite was prepared by the solution intercalation and the liquid-phase reduction methods, and it was characterized by the following analysis methods: SEM, TGA, FT-IR and XRD. The performance of this composite coupled with extracellular respiratory bacteria (Shewanella oneidensis MR-1) on 1, 1, 1-trichloroethane removal under anaerobic conditions was studied, and the optimal conditions for this composite application was determined. Furthermore, the possible mechanisms of 1, 1, 1-trichloroethane removal in the synergistic system were discussed. The results showed that in this composite, both nano-zero valent iron and polylactic acid particles dispersed homogeneously on the biochar surface. The optimum mass ratio of biochar, polylactic acid and nano-zero valent iron in the composite was 7∶1∶2, and the optimal dosage of this composite was 1.0%, at which the contaminants with various concentrations could be removed effectively. After 360 h-incubation, the maximum removal rate of 1, 1, 1-trichloroethane was 94.61% under the optimal application conditions. In the synergistic system, the main mechanism of contaminant removal was the dissimilatory iron reduction dechlorination of extracellular respiratory bacteria promoted by this composite. An synergistic process between this iron-based biochar composite could effective couple with extracellular respiratory bacteria to improve the removal rate of 1, 1, 1-trichloroethane in aqueous solution, and had good slow-release and long-acting properties.