Sound field separation is a kind of pre-processing technology to achieve accurate sound field reconstruction. In order to improve the two hologram plane separation technology, there are many points and the separation accuracy is affected by the distance between the two hologram planes. A single hologram field separation method on equivalent source method is proposed. The approximate location of the near field sound holography technology of space transformation, and the separation formula of sound and normal vibration velocity is established by combining the relationship between sound pressure and normal vibration velocity in the equivalent source method. The separation results of pulsating ball as a sound source are simulated and analyzed. The results show that this method has a good separation accuracy. It is seen that this method can realize the effective separation of multiple coherent sound sources under a single measurement surface.