We propose a design method for off-axis meta-lens and analyze the effects of numerical aperture, off-axis angle, and incident wavelength on the simulation deviation, resolution and focusing efficiency of off-axis meta-lenses. Several off-axis meta-lenses with parameters NA=0.408 α=13°, NA=0.180 α=13°, NA=0.408 α=20° were simulated by Lumerical, respectively. The simulation results indicate that the off-axis angle is directly proportional to the spectral resolution. As the angle increases, the spectral resolution becomes better, but the focusing efficiency decreases. A smaller numerical aperture result in a smaller coverage of the phase distribution, leading to a larger deviation between the simulation and theory. Designers need to reasonably balance parameters such as numerical aperture and off-axis angle according to the requirements to finally achieve the desired effect. This study has an important reference value for theoretical analysis and parameter design of off-axis meta-lens in practical application.