Herein, a differential modulation computational ghost imaging method based on discrete W transform is proposed. The light source is differentially modulated by two sets of discrete W transform basic patterns: positive and negative, and the spectrum of the target object is obtained according to the light intensity measured by the barrel detector. The target image is reconstructed by inverse discrete W transform in matrix form. The proposed method is verified by both computational simulations and laboratory experiments. The results show that the method can obtain an image from compressive measurements. The background noise can be removed by differential measurement to realize excellent image quality, and the image can be reconstructed quickly by applying the inverse discrete W transform. Compared with other methods, this method offers more advantages in terms of imaging quality.