To provide a real loading environment for structural design, product life estimation and health assessment, it is important to correctly identify the dynamic load and its position. In this paper, the frequency domain method is used to study dynamic load position determination, and an equivalent load error method based on the vibration characteristic of the linear elastic system is proposed. This method constructs an object function with equivalent load error values at the same location from different measuring points. The actual position is where the equivalent load error is the smallest. Simulation on the tablet is perfect with both single point drive and double points one, and the method is still valid when noise is added. It provides the basis for complex structures and the determination of multiple loading locations. The experimental verification on a simply supported beam shows that this method can correctly identify the dynamic load location, is not sensitive to noise, and has good prospects for engineering applications.