An optical head for reading an object includes a hollow housing, a light source module, a diffuser structure and a light sensing module. The light source module is fixed in the hollow housing and provides an initial light ray. The diffuser structure is connected the hollow housing, receives the initial light ray, and processes the initial light ray into a uniform light ray for output. The initial light ray is reflected by the diffuser structure multiple times to form the uniform light ray. The light sensing module is fixed in the hollow housing and senses the uniform light ray reflected by the object. An optical axis of the light sensing module is substantially parallel to an axial direction of the diffuser structure.