The effect of Sapindus mukorossi peel extracts on the growth of weeds in corn fields at Huangjia town of Tongcheng city in Anhui province, China was determined. The results showed that the testa extracts of Sapindus mukorossi alone or mixed with herbicides could significantly inhibit the emergence and fresh weights of weeds in corn fields. The aqueous solution (AS) of 30% extracts inhibited emergenceof Sapindus mukorossi was more than 82% and 87% of Digitaria sanguinalis and Ludwigia prostrate, respectively and the fresh weight of these weeds was controlled above 85% after spraying for 15 d or 30 d at doses of 3900-4500 mL·hm^-2, respectively. For Cyperus rotundus, the inhibited emergence was more than 75%, and fresh weight was more than 82%. The inhibited fresh weight to all weeds was more than 83%. When the two herbicides, namely alachlor (PC 20%) and oxadiazon (PC 6%) was mixed to used, with reduced dosage of chemical herbicides, would significantly inhibited the growth of weeds. The 4500 mL·hm^-2 of the mixture with alachlor markedly inhibited emergence (>90%, 94% and 79%) for Digitaria sanguinalis, Ludwigia prostrate and Cyperus rotundus, and fresh weight (>88%). The 3600 mL·ha^-1 of the mixture with oxadiazon could markedly inhibit the emergence in more than 94% and fresh weight in more than 96%. Sapindus mukorossi may have inhibitory potential on weeds as a natural corn field herbicide.