Abstarct: Underground caverns have an important role in the principal nations infrastructures e.g. oil and gas, electricity and communication, military, nuclear, sewage, tourism, food, etc. Large rock or salt caverns are used for storage of variety type of hydrocarbons in oil and gas industry. In rock caverns, liner system or water curtain controls fluid leakage and prevent environment contamination. In Iran, feasibility study of underground storage in rock caverns has been commenced in the middle of 80’s. Therefore, in this thesis, the process of conceptual design of Genaveh rock caverns for storage of 10 Mbbl crude oil is clarified. The main scopes of this thesis are geometrical design, preliminary support system selection and evaluation of parameters that affect stability of caverns. Conceptual design process is done with numerical method and FLAC3D software. Thus, the cavern dimensions are 15 m in width, 20 m in height and 500 m in length. Caverns distances are between 40 m to 50 m and their depth are about 100 m below the ground surface. Because of the geomechanical and hydrological properties of Aghajari formation, liner system is essential for oil leakage prevention. Determined support system of cavern consists of shotcrete and fully grouted rock bolts. The thickness of shotcrete is about 30 cm, the length of rock bolts are about 12m in the crown and 15 m in the walls and their diameter is 32 mm. In parametric analysis, shear strength is the most sensitive parameter and in sensitivity analysis, aspect ratio is the most important parameter.