Rewritable organic optical-recording media which are composed of dye-polymer bilayers were prepared and the effect of their structures on the recording properties was investigated. The recording layer consists of thermal-curable poly-urethane resin and a cyanine dye, and the retention layer consists of poly-styrene resin and a quinone dye. The carrier to noise ratio(CNR) of the recording media increased as the thickness of the retention layer decreased. The composition of the media was varied to find out the optimal point. The complex refractive indices of the media were calculated to simulate the marked bump height and the temperature distribution of the media. Here we discussed the effect of bump height and the thermal expansion coefficient(alpha) on CNR of the media.