In order to realize the measurement for Modulation Transfer Function(MTF) of an on-orbit hyperspectral remote sensing system, factors of image quality degradation of the system were analyzed and the detection method for MTF was discussed by taking the dispersive hyperspectral remote sensing system for an example. Firstly, the three-dimensional separability of the MTF of the dispersive hyperspectral remote sensing system was illustrated.Then, an anti-noise MTF detecting technique was proposed concerning the charateristic of the low signal-to-noise ratio of the hyperspectral remote sensing system. A criterion of selecting MTF detection region was also proposed based on the large quantity of the bands in hyperspectral systems. Finally, the proposed methods were demonstrated by using the PHI remote sensing images and the PHI degraded images were restored with the detected MTF. Experimental results indicate that the average gradient has been improved by 67.1% and the detail-signal energy improved by 65.2%, which proves the effectiveness of the proposed method.