In view of the questions for the rock anchor foundation used in the actual transmission line project, and the need to provide the supporting capacity, the bond strength between anchor bar and concrete and so on for the rock anchor foundation design, loading test was carried out for real foundations in working conditions of the vertical uplift or the three-directions loading. Based on the model failure manifestation of foundations, the load-displacement relations, the anchor bar strain-buried depth relations and so on, have analyzed the main failure state and the load-supporting characteristics, as well as the anchor bar transmission load characteristic. The findings indicated that the rock anchor foundation may be used in the medium and strong weathered rock distribution region, and has the good economy and the social efficiency. There is an obvious first inflection point in the load-displacement curves, corresponding to the displacement of less than 10mm. the higher degree of weathered bedrock is, the smaller foundation bearing capacity is, and the greater displacement is. And the horizontal load has the adverse effect to uplift stability the group anchor foundation.