Hydroseeding is one of the most efficient methods for erosion control and scenic improvement along highway. The purposes of the experimental program were to find the effective cementing materials and grass seeds for various seasons and proper hydroseeding methods for vegetative stabilization of the cut slopes. The experiments were conducted at Ta-Kang, an elevation of 100m; Yu-Chyr, Nantou, an elevation of 700m and Song-Kang, an elevation of 2,000m. Weeping love grass, Bahia grass, Bermuda grass and White clover were used and mixed with asphalt emulsion as cementing material. The mixture of grass seed, fertilizer and water and asphalt emulsion was shot to the cut slope by a portable hydroseeder carried on the back. The asphalt emulsion had concentrations of 1:1, 1:2, 1:3, 1:4, and 1:5, a ratio of asphalt emulsion to water in weight. The two hydroseeding methods included spraying the mixture of the seed and asphalt emulsion and spraying the seed first, then the asphalt emulsion. The grasses were hydroseeded in February, April, and September, 1973 at above-mentioned three spots. The seedlings of grasses were counted on the replicated plots about 15,45, and 90 days after they were seeded. The results from the data analyses of 90 day growth are summarized as follows: 1. The cementing material of asphalt emulsion was proved effective in providing stability for the grass seeds and seedlings, especially when the grass seeds were hydroseeded during rainy season. The grass seedlings in the plots of 1:2 and 1:3 concentrations of asphalt grew better than those in other plots. 2. Two hydroseeding methods were compared at Song-Kang in September 1973. No significant difference showed in the seedlings of Bahia grass plot and Bermuda grass plot with two methods. The method of spraying seed first, then the asphalt was proper for hydroseeding White clover. while the method of spraying the mixture of the seed and asphalt for Weeping love grass. 3. The Bermuda grass plots had significantly more seedlings than the Weeping love grass and Bahia grass plots about three months after they were hydroseeded in September, 1973 at three experimental spots. This seemed to indicate that Bermuda grass could tolerate cold and dry weather. There was no significant difference in the seedlings of Weeping love grass and Bahia grass plots. The grasses hydroseeded at Ta Kang grew better than those at Yu-Chyr and Song- Kang 4. The Weeping love grass hydroseeded in February and April grew better than that in September while there was no significant difference between that in February and in April. This seemed to indicate the effect of temperature on the growth of Weeping love grass. 5. The White clover hydroseeded in September at Song-Kang grew much better than other three grasses used. As various seasons is concerned, the White clover hydroseeded in February had significantly more seedlings than those in April and September. So it is advisable to hydrogeed White clover in spring.