Quantitative methods have been formed to measure the spatial resolution in spectral imaging field, but the results may differ with imaging position change when the resolving power of detector is deficient. Based on the spectral images of black-white lines under accurate shift, a new method for detecting the spatial resolution of area array spectral imaging equipment is proposed. This method presents the curve showing the gray level variation with the displacement of object for a single pixel, and can obtain all the results of gray level distribution among pixels theoretically. Through one type of curve division, the density value of the black-white lines which can be discerned on any imaging position will be obtained. This method has overcome the shortcoming of current methods, and its fea-sibility is validated by an experiment for one area array spectral imaging equipment.