Metalens has the prospective to replace the traditional lens for multifunctional sub-wavelength imaging due to its thinness and ease of integration. The beam deflection angle of the metalens increases with the increase of wavelength and produces opposite dispersion compared to the traditional refractive lens. This form of dispersion is also called "abnormal dispersion" or "negative dispersion". Theoretically, the negative dispersion of the metalens and the positive dispersion of traditional refractive optical devices can be used to fully offset the chromatic aberration of the optical system. Consequently, this study demonstrates the design of an achromatic metalens compound lens based on photoresist material by employing Pancharatmane-Berry (PB) phase metalens as the first lens and traditional spherical lens as the second lens, through finite difference time domain method. The focusing characteristics of the lens at λ = 780～980 nm are investigated by FDTD Solutions (a numerical simulation software) and an exceptional achromatic effect of photoresist metalens compound lens is realized. Compared with the traditional achromatic metalens, the achromatic design is simple and efficient which provides a certain significance for achromatic imaging in the specified bandwidth.