With the construction of large oil storage tank farm, the requirements of the tank installation are stricter. To 1.0×10 ⁵ m ³ of crude oil storage tank as an example, the installation technology of tank bottom was introduced and discussed. The installation technology of tank bottom was described in detail under the standard of high standards and low consumption,such as positioning, center plate laying, technical requirements of tank bottom laying, T-fillet welding, the welding to influencing factors of annular to mediate joint. In order to ensure the accuracy of the corridor lay board, assembly sequence of the tank bottom was innovated. The corridor board was used only one time. To achieve the positioning of the corridor lay and welding in one time, the whole process of construction use the domestic mature technology to ensure that the construction tasks are completed with high quality and efficienty.