The invention provides an off-axis multiplexing hologram zero-order image elimination method based on numerical iteration. The multiplexing hologram zero-order image elimination method through successive iteration is firstly put forward. A primary spectrum is obtained through frequency domain windowing, a zero-order image is constructed through computation, and the constructed zero-order image is subtracted by a multiplexing hologram so that the multiplexing hologram of which the zero-order image is eliminated through one time of iteration can be acquired. Frequency domain windowing is performed on the multiplexing hologram after one time of iteration to construct the zero-order image, iteration is performed for multiple times and successive windowing iteration is performed on other primary spectrums so that the zero-order image of the multiplexing hologram can be eliminated. According to the zero-order image elimination method, information of an object does not need to be known in advance, and only one multiplexing hologram and reference light information of all sub-holograms are required. The object light information restored by the multiplexing zero-order image elimination method is more accurate than that of the conventional frequency domain windowing method so that space bandwidth of a CCD can be effectively utilized, computation can be performed in real time and operability is higher. Besides, convergence of the method is also analyzed.