This experiment was carried out to study on the most effective method to improve natural grass land into pasture and result s of experiment are as follows. 1. Materials and methods. This experiment was designed with five treatments and three replications; completely plowed, unplowed, halt plowed, manured and nontreated plots and these were managed according to cultivated method in this station. 2. Results ① Yields of pasturage in each treatment are as follows, compared to 100% of nontreated, completely plowed 670%(1,890㎏/10a) unplowed 537%(1,514㎏/10a) half plowed 552%(1,472㎏/10a) and manured 168%(475㎏/10a) ② In economical view, total investigation fox three years and profit per 10a were as follows : completely plowed 2.134won(9,204won), unplowed 2,094won(6,99won), half plowed 1,903won(6,929won), manured 1,650 won (198won) and non treated 170won (927won) profit. ③ Crude protein % of green grass in each treatment were as follows, completely plowed 2.99%, unplowed 2.60%, half plowed 2.60% manured 1.15 and nontreated 1.13%. 3. Conclusion Completely plowed method is most effective to improve the southern part flat natural grass land on which wild grass is not well growing, unplowed method was effective to improve mountain field on which wild grass grows thick, half plowing method was effective, however it tooks long period to improve inclined field and manuring method can be used temporarily to make ore or two year grazing pasture in countries where wild grass grows well.