As a fast and nondestructive detection method,spectral detection is gradually applied in more and more fields. With the continuous improvement of information accuracy requirements,obtaining spectral information with high resolution and low wavelength error is a primary challenge that researchers must face when designing spectral detection systems. Studying a new type of dispersive element becomes a feasible scheme. Traditional dispersive elements,such as diffraction gratings,have an extensive wavelength response range but usually can provide a resolution of the order of nm and cannot meet the requirements of the current hyperspectral resolution. Virtual Image Phased Array (VIPA) has the characteristics of large angular dispersion and high spectral resolution,which can effectively improve the spectral resolution of the system. Therefore,it has been continuously used in the research of fine spectral detection in recent years. However,the corresponding relationship between the wavelength and the dispersion angle is nonlinear,and the same wavelength is prone to generate multiple diffraction orders,resulting in additional light energy loss. Therefore,based on the cross-dispersion optical path of VIPA,this paper conducts theoretical analysis and experimental verification on how to reduce the dispersion nonuniformity of VIPA. Firstly,based on the dispersion law of paraxial theory,the influence of the incident waist size,incident angle and other parameters on the nonlinearity of VIPA dispersion and the number of diffraction orders is analyzed theoretically.The number of diffraction orders of each wavelength and the calibration value of the spot centroid corresponding to each wavelength of the broad spectrum light source at different VIPA tilt angles are recorded through simulation. The linearity under different angles is compared by calculating the average distance difference between the centroid coordinate and the fitting curve in each case. Finally,the experiment is carried out according to the theoretical analysis and the simulation results. The number of diffraction orders of the cross-dispersion optical path of VIPA under different VIPA tilt conditions was recorded in the experiment,and the centroid coordinates of each diffraction order spot of different wavelength light sources under the experimental condition of VIPA tilt of 2° are obtained by using a variable wavelength laser. Similarly,the linearity of different diffraction orders is analyzed by calculating the distance average between the centroid of different diffraction orders and the fitting curve. The results show that the nonuniformity of VIPA dispersion can be reduced to some extent by controlling the parameters of the incident beam.The larger the tilt angle of VIPA and the closer to the center of the detector,the better the diffraction order linearity.