At present, in the superresolution technique most of pure amplitude or pure phase filters only can realize transverse or axial superresolution, but cannot aehieve the three-dimensional superresolution which play an important role in the three-dimensional imaging systems. So in order to improve the three-dimensional resolving power of optical imaging system, a new set of complex amplitude pupil filter is designed, and its three-dimensional superresolving performances are studied. The effects of the radius and the transmittance of the first zone on the Strehl ratio, the transverse and axial gains, and the side lobes are analyzed in detail. With a series of simulation examples of such filter, it can be concluded that three-dimensional superresolution can be realized with the compleamplitude pupil filter. Advantage of such filter is easy to realize three-dimensional superresolution with high Strehl ratio. And disadvantage is that the influence of the side lobes is greater for some systems. But it can be suppressed by applying confocal scanning imaging systems.