Key module with multi-layer light guiding structure

A key module with a multi-layer light guiding structure includes a plurality of keys, light guiding structure and a plurality of light blocks corresponding to the light guiding structure. The light guiding structure includes a plurality of light guiding plates. Each of the light guiding plate includes at least one light guiding strip corresponding to specific keys, which are staggered to each other or corresponding to each other. The light guiding strip is provided with a color layer. An electronic device using the key module individually or selectively lights light emitting elements for each layer of the light guiding plates. Therefore, different lights are emitted from the light guiding strips or a mixed light is produced from the light guiding strips to illuminate the keys. The keys have lights of different color to manifest symbols or alphabets on the keys.