Based on the test technique of RapidAir and MAP BEI, pore structure and microscopic interface of dam concrete with different aggregates were studied. The results show that with the definite mix proportion, the limestone concrete has the maximum amount of bubbles and the minimum space coefficient and average pore size, while the sandstone concrete leads to the opposite results, which should be paid enough attention. The enrichment of Ca（OH）2 in the interfacial transition zone（ITZ） is affected by chemical and physical properties of aggregates（such as long term water absorption）. The degree of Ca（OH）2 enrichment and interface thickness are increased in the order of sandstone＞basalt＞limestone and sandstone＞limestone＞basalt. Sandstone concrete has the weakest interface structure.