Abstract: To investigate the feasibility of equivalent pendulum model of sloshing of fluid in a cargo tank truck with a circular cross-section, a precise computational model for the inclination of the liquid free surface and centroid coordinates was constructed by using the fluid Euler equations under a non-inertial system and the centroid calculation formula for homogeneous planar body. It was found that,under the lateral acceleration, the trajectory of the liquid centroid forms a circular arc with the tank cross-section center as its center point.Based on the results, a pendulum model was established with the line connecting the liquid centroid and the tank center as the equivalent pendulum length. Theoretical calculations and Computational Fluid Dynamics (CFD) simulation-based technique were adopted to obtain pendulum vibration curve images under corresponding conditions respectively.The pendulum vibration curve images indicates the feasibility of considering sloshing of fluid in a tank truck with a circular cross-section as pendulum vibration, effectively reflects the variation patterns of sloshing of liquid and facilitates the calculation of the reaction forces exerted on the tank inner wall during liquid sloshing. The conclusion of research provides a theoretical basis for studying the roll stability of a cargo tanker truck.