The middle reach area of the “One Rive-Two Streams”watershed is a region in Xizang Autonomous Region where the industrial and agricultural economy is most concentrative and developed. In this area, animal husbandry occupies an important position in the agricultural economy. This paper illustrates the state of the grassland resources and the characteristics of the productive force and the distributive regularity of the grassland of the area. The study has found that the grassland area is about 5.254 million ha, the grassland types are relatively complicated, the vertical distribution of the grassland is obvious,the forage composition relatively plentiful, and the nutrition value of the forage is relatively high. But the grassland productive force is relatively low. The average yield is about 1275-1350kg/ha. Viewed from the horizontal distribution pattern of the grassland resources, there is an obvious diversity between the north and the south. The proportion of the grassland on the north side of the Yaluzongbu River exceeds 63%.Viewed from the distribution time of grassland, the season diversity is notable. The grassland yield in winter is only 10-30%. But the composition and the distribution pattern of the forage grass in this area coordinate with the animal husbandry and they jointly form a relatively coordinative grassland-animal husbandry unity.