Molten salt is often used for heat transfer and thermal energy storage in concentrated solar power. Molten salt leakage and migration is a significant issue in its application. Molten salt migration and solidification in thermal porous foundation ma-terials through cracks are experimentally investigated. The impact of factors, including crack length and width, operation tem-perature, and leakage mass of molten salt, are studied through an experimental device modeling the leakage of the actual molten salt storage tank. Experimental results show that the crack width and length slightly affect the migration depth, but directly affect the shape of the agglomeration of solidified salt and porous foundation material. The most important factor affecting the migration depth of molten salt leaking through cracks is the tank operating temperature. The molten salt migration depth when the operating temperature is 500 ℃ is 95.8％ higher than that with an operating temperature of 300 ℃. As the leakage molten salt mass reached 400 g, the average migration width increased by 23.6％, but the migration depth only increased by 5.2％. It is found that the foundation material temperatures after leakage accidents increase with an increase in the mass of leaked molten salt.