An equivalent source model based on neural network is proposed to rapidly estimate the magnetic radiation characteristics of linear synchronous motor (LSM) in electromagnetic suspension (EMS) maglev system. The equivalent source is composed of electric dipoles and a closed three-dimensional (3-D) surface, and is developed in terms of source reconstruction method. A few sampling data of magnetic field simulation results serve as the input information to determine the unknown current distribution on equivalent source model. To solve the inverse radiation problem and characterize the whole radiation pattern with high efficiency, the current distribution signature of equivalent model is fitted into artificial neural network models. Separate neural network models are fitted under different phases of winding excitation, which enables the low-frequency magnetic field estimation under both 3-phase balanced operation and unbalanced operation. The equivalent source model is extended to estimate LSM radiation in multi-source environment, and the comparison with numerical simulation verifies its accuracy and efficiency.