To understand the influence of the vortex generator on the aerodynamic drag reduction characteristics of heavy-duty trucks, a Chinese heavy-duty truck was taken as the research object to study the influence of the shape, arrangement position, height and gap ratio of the vortex generator on drag reduction effect of the truck based on the numerical simulation of computational fluid dynamics. The reason for drag reduction was discussed from the aspects of velocity streamline structure, turbulent kinetic energy distribution, and pressure distribution. The results show that the shape, arrangement position, height and gap ratio of the vortex generator have a great influence on the aerodynamic drag of the heavy-duty truck. The fork-shaped vortex generator has the smallest aerodynamic drag coefficient when it is located at the rear end of the cargo compartment, and its value is 0.699 6. Compared with the original model of the truck, the drag reduction rate is 11.7%, indicating that the fork-shaped vortex generator is the best vortex generator shape. The installation of the vortex generator can reduce the area and strength of the vortex zone of the rear of the truck, and delay the separation of the tail airflow, thereby reducing the differential pressure resistance of the front and rear parts of the truck.