Abstract: In this experiment,loach(Misgurnus Anguillicaudatus) was used as the biological indicator to evaluate the capacity of carbon K in purifying wastewater from a pig farm.Using tap water,which had been exposed in open air for 3 days,as the control,loaches were fed in water containing 11.1% pig farm wastewater with or without carbon K.The SOD and GOT activity in the liver of the loaches were determined after 12h,36h,60h and 84h.The results showed that after 12 to 36h in the contaminated water,there was an upward trend on the activities of SOD and GOT in the loaches.The activities gradually decreased with contact time.In contrast,the loaches that were raised in either the tap water or contaminated water with carbon K had a similar change in those enzymatic activities during the same time period.The t-test indicated a significant difference on SOD and a highly significant difference on GOT activities between the two groups and the contaminated water group.It was concluded that the pig farm wastewater was toxic to loach affecting its physiology and biochemistry,and that carbon K could be an effective agent used to purify the wastewater from a pig farm effluent.