Forty six individuals out of 200 Acronicta rumicis larva were parasitized (23 %) in 2000, 14 individuals out of 60 (23.33 %) in 2001, and 14 individuals out of 62 (22.58 %) in 2002. The mean parasitism rate was $22.97{pm}0.38%$. The parasitism rate was 36.36 % in May and 52.78 % in October, 2000, 75 % and 50% in May and October 2001, 71.4% and 47.37% in May and October 2002 and it was much higher than other months. Parasitism was occurred from May to October 2000, but it was not in June and August 2001 and June 2002. There was no difference in the monthly mean parasitism rate, but the rate was the highest in May and October. The parasitoid of the larva of A. rumicis was the highest by 77.02% of parasitic wasps, and 13.51% of parasitic flies. It was found that multiparasitism was 4.05 % and hyperparasitism was 5.41 %. In case of parasitic wasps whose parasitism rate is the highest, the rate of Braconidae and Ichneumonidae was 70.18 % and 29.82 % respectively. That is, the former has much higher parasitism rate. The parasitism rate of the larva of A. rumicis was found that Microplitis sp. is $5.28{pm}0.63%$, Glyptapanteles liparidis $8.62{pm}3.70%$, and Diadegma sp. $4.02{pm}1.28%$ respectively.