To find out the productivity of temperate grasses on the south and north slope, a field experiment was conducted with five forage species of Cactylis glomerata, Festuca arundinacea, Phleum pratense, Agrostis gigantea and Trifolium repens. It was treated by randomized block design with 4 replications and lasted from September, 1983 to October, 1986 in Suweon. The results obtained are summarized as follows: 1. During the vegetative period for three years, the mean surface temperature and soil temperature at a depth of lOcm on the south exposure were 2.0^{circ}C$ and 0.8^{circ}C$ respectively higher than that of north slope, but the soil temperature between exposures were practically not different in the mid-summer season. 2. Early growth and development of forage species on the north exposure were better than that of species on the south slope. 3. Average DM yield of grasses on the north slope was much more increased than that of species on the south, however, Trifolium repens was more positive in the south. 4. Otherwise average DM yield of Dactylis glomerata and Festuca arundinacea on the north slope was a little more increased, that of Phleum pratense and Agrostis gigantea was much more increased than that of same forage species on the south.