In this paper, a novel interpolation-based subpixel mapping (ISPM) for hyperspectral image by using pansharpening (PAN-ISPM) is proposed. In the proposed method, a novel processing path is added into the existing processing path of ISPM. Firstly, the original coarse hyperspectral image is improved by pansharpening technique in the novel processing path, and the novel fine fraction images are derived by unmixing the improved image. Secondly, the novel fine fraction images from the novel path and the existing fine fraction images from the existing path are integrated to produce the finer fraction images with more spatial-spectral information. Finally, according to the predicted values from the finer fraction images, class labels are allocated into subpixel to obtain the final mapping result. Experimental results show that the proposed method produces the higher mapping accuracy than the existing ISPM methods.