Abstract: The calculation method for the influence quantity is discussed for single-layer multi-span frames under moving load, which are wildly used in bridges, industrial and public buildings. Based on the concept of moment distribution method for continuous beam, the concept of anti-rotation stiffness of bar end and the transfer of node rotational angle is established, and the corresponding calculation formula is proposed. An exact calculation method is put forward to determine the influence quantity of single-layer multi-span frames under moving load. Examples show that the proposed method is simple and feasible.