As a new type of high⁃efficiency mixing equipment, static mixers are widely used in industrial production due to their good mixing effect and simple operation. In this paper, the SK type static mixer was introduced into the crude oil storage tank to solve the problem of uneven distribution of crude oil density. The three⁃dimensional incompressible flow field was numerically simulated by FLUENT. The Eulerian multiphase flow model was used to simulate the velocity field, concentration field, temperature field and pressure field of the fluid in the static mixer. The results show that: under the action of the spiral blades of the static mixer, the crude oil moves cyclically along the opposite direction of the blade and changes periodically. Through the cutting, shearing and rotating action of the crude oil, the oil is almost completely mixed at the exit,which shows that SK static mixer has better mixing effect and less pressure loss and can reduce the energy consumption cost.