An apparatus for measuring a curvature of a thin film includes a light emitting module, a first optical module, a second optical module, a third optical module, and an image analysis module. The light emitting module emits a single laser to be used as an incident light. The incident light is transmitted through a first optical path provided by the first optical module, then the incident light is guided by the second optical module to be incident to the thin film through a second optical path. A reflected light reflected by the thin film is transmitted through the second optical path, then guided by the third optical module to be transmitted along a third optical path. The image analysis module determines the curvature of the thin film according to the characteristic of the reflected light.