This study was carried out to investigate changes in the quality and botanical composition of native pasture during the grazing period. The results obtained were as follows: 1. On all the farms, the total dry matter yield of native pasture was much higher in the October-cut than in the July-cut. 2. The crude protein content was higher in the July-cut than in the Oct.-cut, while the crude fiber content gave opposite results. There was the same tendency on all the farms. 3. When the six farms were compared, the highest crude protein content was found at Hawon and Haian farm, and cows on these farms showed the highest daily weight gain. Ohra farm had the lowest crude protein and the cows on this farm the lowest daily weight gain. 4. The botanical composition of the main species distributed was 58.1% Zoysia japonica, 16.4 Pteridum aquilinum, and 3.8% Miscanthus sinensis. In the case of family, 72.1% were Gramineae, 1.8% Leguminosae, and 16.4% Pteridacea. 5. According to botanical composition of a family, Hawon farm had the highest daily weight gain and the highest rate of Gramineae and Leguminosae. Ohra and Youngkang farms had the lowest weight gains, but the native grassland on these farms contained a high proportion of Pteridum which is toxic to cattle.