Abstract: Multi-parallel beam (MPB) collimator with three channels was designed by introducing the multiplexing. The simulation study indicates that the system sensitivity is improved while maintaining a higher spatial resolution. The simulation of uniform cylinder phantom indicates that reconstructed ring artifacts are not appeared in reconstructed image as iterative number increasing. The simulation of Jaszczak phantom indicates that the spatial resolution of MPB collimator gradually approaches to the parallel-beam as depth increasing although the resolution descends near the collimator front face. The uniformity of reconstructed image is improved. The overlapping of projection data indicates that there is projection amplification for the MPB collimator. This study provides a way to design high quality SPECT image.