Organically combined linear interpolation and sine gray level transformation, a new infrared image interpolation and zooming method has been proposed. Firstly, bilinear interpolation method is adopted to calculate the interpolation points as the preliminary interpolation. And then S-shaped sine gray transformation curve is used to enhance processing as the final interpolation. The method makes full use of the simple algorithm and small computational amount of the linear interpolation, meanwhile reduces the effect of image edge blurring brought by linear interpolation. Experimental results show that method of interpolation is better than traditional bilinear interpolation.