Most of earth rock dams use roller compacted asphalt concrete as impervious core wall. In this paper, the conditions of hydraulic fracturing of asphalt core wall in dam are studied. Firstly, the asphalt concrete test model is established, and the model is tested under constraint and compression conditions. The test results show that the fracture model of asphalt concrete is not so-called “hydraulic splitting”, but caused by the large strain of asphalt concrete under the external conditions. In this paper, the hydraulic fracturing condition of impervious asphalt concrete is studied. The results show that the hydraulic fracturing condition is very severe for the asphalt core wall in the dam, so the so-called “hydraulic fracturing” can be excluded.