A light emitting device, a light receiving device and a data transmission system and a data transmission method using the same are provided. The data transmission system includes the light emitting device and the light receiving device. The light emitting device includes a light emitting unit and a control circuit, and the light receiving device includes an image capture unit, a recognition unit and a decoding unit. The control circuit controls the light emitting unit to sequentially display a plurality of pattern images in a plurality of frame times to form a spatiotemporal pattern image according to setting data corresponding to a temporal domain and a spatial domain. The image capture unit captures the spatiotemporal pattern image. The recognition unit recognizes the spatiotemporal pattern image to output recognized data. The decoding unit decodes the recognized data to output decoded data.