With the rapid development of the world's strategic oil reserve construction, large-scale storage tanks become a trend, therefore the high-strength steels are used to build single-walled large cylindrical storage tanks at present, but the maximum capacity of single-wall steel tanks built by the high-strength steels is 20 × 104m3for the restriction of the plate thickness and weld performance degradation, so the design ideas must be changed in order to build much larger capacity storage tank, namely using the hydraulic balance principle to solve the problem. The design of hydraulic balance tank was proposed. Through the introduction of the design form of the tank and the analysis on example of tank wall strength calculation, it is found that the much larger hydraulic balance storage tanks can be built by steels of ordinary grade with the cost greatly reduced and security slightly increased. Therefore, it is feasible in design, desirable in economy and reliable in safety to use the hydraulic balance structure to build much larger oil tanks.