This paper presents a method for enlarging holographic images under the constraints of spatial light modulators. The proposed method involves using a modified Gerchberg–Saxton algorithm and spatial multiplexing to segment images and projection surfaces. Segmented element images are processed to create multiple phase masks, which are then stitched for image reconstruction. Experimental results indicated that the proposed method enabled effective magnification under different segmentation methods. This method allows the enlargement of holographic images without using additional lenses, thus enabling effective magnification to be achieved with a limited setup. Reconstruction results indicate that the proposed method can produce a magnification of up to 16×.