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The traditional optical system is composed of multiple optical elements, which will lead to the huge volume and high cost of the optical system, which can not meet the needs of people in terms of performance. The emergence of metasurface has made a great breakthrough in the problems existing in optical systems. In recent years, the metasurface has attracted the attention of researchers because it can breakthrough the limitation of traditional electromagnetic law and realize the modulation of light phase, amplitude and other parameters. In this paper, a kind of multiwavelength confocal plane multifocal metalens in visible wavelengths is designed. The design of metalens is realized by computer generation holography(CGH), and the phase distribution of the metalens is analyzed and calculated. Transmission metalens designed with all-dielectric materials is used and the imaging effect of confocal plane four-focal metalens at different wavelengths of visible wavelengths is analyzed. The surface phase characteristics of the multifocal metalens at different wavelengths were analyzed, and the Pancharatnam-Berry (P-B) phase was used to match the rotational phase of the unit cell structure with the phase of the surface of the metalens, and the confocal plane focusing at multiple wavelengths was successfully realized, with the focusing efficiency reaching 43%.
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