Abstract. Vertical metal tank is an important compulsory verification metrology instruments of energy trade transfer in China. The metrology of its capacity is accurate or not, directly affecting economic interests and national metrology reputation at home and abroad. In the paper, through the establishment of 50000m3 vertical metal tank bottom finite element model, the tank weight and the water static pressure conditions are simulated, and vertical metallic bottom stress analysis and research is carried out. Respectively vertical metal tank volume of 1000m3,5000m3,10000m3 were simulated and analyzed at different heights of the tank water level , summarizing the deformation law of tank bottom. Compared capacity comparison method with geometric measurements method by a volume of 5000m3 vertical metal tanks , the reliability of the simulation conclusion is verified. The empirical formula is to be modified, thereby improving the accuracy of capacity of trade transfer metering and ensuring the safe use of the tanks.