A series of batch-type experiments with acetate acid as the primary substrate were performed using enrichment cultures developed from the anaerobic sludge to investigate the effect of acetate acid on tetrachloroethylene (PCE) biodegradation. Experimental results indicated that acetate acid was an efficient electron donor in affecting the biotransformability of PCE. Trichloroethylene (TCE) was the primary dehalogenation product, and small amounts of dichloroethylenes (DCEs) were also detected. No significant further DCEs degradation was detected. PCE degradation rate in the experiment was 36.6 times faster than background rate in natural groundwater.