Abstract: The survival strategies of grasses and legumes in mixed stands under different environmental circumstances, such as light, nutrient, moisture and living space are discussed. First, the competitive and stimulative relationships between the legume and grass species which constituted the mixed stands are described. Then, the factors affecting the ability of nitrogen fixation and transportation in legumes were analysed together with the community coexistance mechanisms of deep legume roots and shallow grass roots. Finally, it is proposed that the competition between species in mixed stands can be weakened or avoided to improve their productivity and to maintain the endurance and stability of the mixed stand through mixing technology, grassland management, and patterns of exploitation.